“两系法”和“三系法”杂交水稻是利用杂种优势的2条重要途径[1⇓-3]。与以核质互作雄性不育为技术核心的“三系法”杂交稻相比,“两系法”杂交稻（简称两系杂交稻）是利用光温敏核不育系与恢复系杂交制种,具有一系两用、无需保持系、育种流程简化和杂种优势强等优点,是继“三系法”杂交稻后杂种优势利用的重大科技创新[1⇓-3]。近年来,两系杂交水稻在我国的年种植面积已超过500万hm2,成为水稻杂种优势利用的主要途径,为保障我国粮食安全发挥了至关重要的作用[3-4]。但光温敏核不育系的育性转换受光温条件影响：在杂交制种期间如遇低温（≤23℃）,不育系可自交结实导致杂交种子纯度不高;若遭受到高温胁迫（≥35℃）会导致开颖障碍和雌性器官（雌蕊）不能正常受精,使制种产量严重下降,造成巨大的经济损失[4⇓⇓⇓⇓-9]。
随着全球工业化的不断发展,温室效应增强,全球气温随之增高,预计到21世纪末可能上升4℃~5℃。水稻生长季夜间温度每升高1℃,水稻产量可能减少10%[7]。高温胁迫已成为包括“两系法”杂交稻制种在内的水稻生产的一个主要危害[3,7⇓-9]。以我国一个重要的两系法杂交制种水稻基地江苏省盐城市为例,2010至2020年间,有5年（2010、2013、2016、2018和2020年）在杂交制种期间遇到不同程度的高温危害,导致制种产量大幅下降,尤其是2013年的高温导致两系杂交稻较正常年景减产80%~90%,产量和经济损失巨大[10]。因此,了解水稻光温敏核不育系响应高温胁迫的机理,掌握减轻其高温危害的调控途径与技术,对于提高两系杂交稻制种产量和指导水稻抗高温育种、栽培具有重要意义。为此,本文综述了高温胁迫对水稻光温敏核不育系开颖、雌蕊受精以及影响抽穗的生理机制研究进展,讨论了减轻高温危害的调控措施,并对今后研究提出了建议。
1 高温胁迫导致水稻光温敏核不育系开颖障碍的生理机制
水稻开花包括颖壳张开（主要是外颖张开）、花丝伸长、花药开裂、花粉散落在柱头上、花粉萌发和花粉管向子房伸长等过程。正常开颖（外颖张开）是水稻完成受精的先决条件[11]。水稻外颖基部的1对浆片吸水膨大,变厚脱开内外颖的沟槽,再变宽把外颖推开,即颖花开颖;当浆片失水时,外颖在小穗轴弹性力的作用下会向内颖靠拢,完成闭颖过程。浆片渗透势降低是其吸水膨大的重要条件;浆片中淀粉通过淀粉酶水解成为可溶性糖,以及外部水分和养分的输入是浆片渗透势降低（或浆片细胞压力势增大）的主要原因[11⇓-13]。此外,钾离子（K+）也是植物极为重要的渗透调节物质,在百合、玉米和黑麦等植物浆片渗透势变化中起关键作用[14]。但水稻开花前与开花时浆片中的K+浓度并没有明显变化[13]。由此推测,对于浆片中不含造粉体的植物（如百合、玉米和黑麦等）,K+等无机离子浓度变化在浆片渗透势变化中起主导作用;而对于浆片中具有造粉体的水稻等作物,浆片中渗透势变化则主要取决于可溶性糖含量的变化[14]。王忠等[15]进一步观察到,适度增温有利于加强呼吸,增加颖花中二氧化碳浓度,使浆片细胞壁松弛,从而诱导浆片吸水膨大,促进开颖。Chen等[6]观察到,开花期高温胁迫会显著降低水稻光温敏核不育系浆片中的淀粉和可溶性糖浓度,导致浆片渗透势显著提高、含水量显著降低,进而导致开颖率与颖花受精率显著降低。Yang等[9]也观察到非常类似的结果。这些结果表明,浆片可溶性糖含量的降低是高温胁迫导致水稻光温敏核不育系开颖障碍的一个重要原因。
植物激素作为一类植物自身合成的、具有调节作用的痕量小分子物质,对植物生长发育具有重要的调控作用,目前尚未有五大类经典激素,如细胞分裂素（CTK）、生长素（IAA）、赤霉素（GAs）、脱落酸（ABA）和乙烯直接诱导水稻开颖的证据[16]。近年来,有学者[17⇓⇓⇓-21]观察到,新型植物激素茉莉酸类（JAs）,如茉莉酸（JA）和茉莉酸甲酯（MeJA）,不仅在应对逆境胁迫和调控植物生长发育方面发挥重要作用,还可以诱导水稻和小麦等多种禾本科植物颖花开放。有学者[16]观察到,雄性可育的常规水稻在自然开放过程中,颖花中JA生物合成途径中一些关键基因的表达与内源JA水平变化均表现为开颖时急剧上升,闭颖后随即下降。细胞质雄性不育系水稻在缺乏JA时会通过延缓浆片内渗透调节物质和水分的积累来抑制浆片膨大,导致颖花开颖困难,开花时间分散[18]。开花期高温胁迫会导致水稻光温敏核不育系浆片中JA和MeJA含量显著下降,抑制了浆片中可溶性糖的积累,浆片内渗透势增加,吸水困难,致使颖花开颖受阻[9]。喷施外源JAs,一方面可以增强叶片和浆片的抗氧化能力,及时清除过量积累的活性氧,有效地减轻高温胁迫对细胞质雄性不育和光温敏核不育水稻的伤害[6-7,9-10];另一方面,水稻植株内JAs与浆片基部细胞中的JAs受体结合,通过一系列泛素化反应释放以MYC2（JA信号转导的核心转录因子）为主的转录因子,诱导糖转运体基因的表达,将糖和K+转运进入浆片细胞[16,22],同时JAs也能促进浆片细胞内淀粉水解,从而增加浆片中可溶性糖和K+等渗透调节物质含量,使浆片吸水膨胀,促进开颖[6,10,18]。此外,MYC2也是ABA信号传导的激活剂[23],喷施JAs增加了植物细胞中ABA含量,从而刺激气孔关闭,保存植株水分[24],提高耐热性。据此,有学者[6-7,9]认为,提高浆片中的JAs水平是缓解高温胁迫下开花期光温敏核不育系开颖障碍的一条重要调控途径（图1）。
图1
图1
茉莉酸类和油菜素甾醇缓解高温胁迫下水稻光温敏核不育系开颖和受精障碍的调控网络图
BZR1：油菜素甾醇信号转导的核心转录因子;MYC2：茉莉酸信号转导的核心转录因子。本图根据参考文献[6⇓⇓⇓-10,16,18,22⇓⇓⇓⇓⇓⇓-29]所作
Fig.1
Schematic diagram of jasmonates and brassinosteroids in alleviating heat stress to photo-thermo-sensitive genic male sterile (PTSGMS) rice line
BZR1: the central transcription factor of brassinosteroids signal transduction; MYC2: the central transcription factor of jasmonic acid signal transduction. The diagram is made according to the references [6⇓⇓⇓-10,16,18,22⇓⇓⇓⇓⇓⇓-29]
2 高温胁迫对雌蕊形态与活性影响的生理机制
开花期高温胁迫会造成柱头萎蔫、灼伤,导致柱头面积降低[37-38],不育系获得恢复系（父本）花粉粒的能力明显降低,最终导致受精率降低,杂交制种产量下降[39-40]。高温胁迫不仅影响水稻柱头面积,还会影响柱头外露率。柱头外露的颖花能接受更多的花粉粒,因此其受精能力远高于柱头不外露的颖花[41-42]。柱头外露率与柱头活性有关,高温胁迫使不育系柱头活性显著下降,柱头外露率随之下降[6],导致不育系受精率降低。高温使水稻柱头生理状态发生改变,导致其表面分泌物减少、乳突细胞膜脂过氧化,致使花粉粒不易附着在柱头上,影响花粉的萌发,直接影响水稻的受精与结实[10,22,43]。高温胁迫会显著降低雌蕊细胞中过氧化氢酶（CAT）活性和抗坏血酸（AsA）含量等抗氧化物质水平,破坏其抗氧化系统,导致雌蕊细胞中活性氧（ROS）过量积累,造成细胞膜系统损伤,雌蕊细胞程序性死亡和生理活性显著降低[44⇓-46]。此外,高温胁迫会破坏雌蕊细胞中Ca2+梯度,使得花粉管无法向指定方向生长[47⇓-49];还会显著降低雌蕊细胞中可溶性糖和腺嘌呤核苷三磷酸（ATP）等的含量,导致雌蕊引导花粉管向胚囊延伸过程中的能量供应不足,降低受精率[50⇓-52]。
雌蕊活性与其中的激素种类和含量水平密切相关。Zhang等[45]发现高温胁迫显著降低了日本晴及其高温敏感型突变体雌蕊中IAA的含量与合成水平,进而致使雌蕊活性降低,最终导致水稻受精结实率下降。油菜素甾醇（BRs）是继IAA、GAs、CTK、ABA和乙烯之后发现的第六大类植物激素,普遍存在于植物界,对植物的生长发育过程与抗逆胁迫具有重要的调节作用[53⇓-55]。在高温胁迫下,BRs信号由细胞质膜上的BRs受体感知,通过一系列磷酸化与去磷酸化反应解除对核心转录因子BRASSINAZOLE-RESISTANT1（BZR1）的抑制作用,使其进入细胞核调控BRs响应基因的转录,将BRs信号向下传导,进而提高植株的耐热性[7,25]。高温胁迫会导致植物体内不耐热的蛋白质失活,并诱导植物细胞程序性死亡,从而导致热害的发生[52,56]。喷施BRs可以增加水稻[26]和西红柿[27]等植物体的热激蛋白含量,从而防止蛋白质变性并促进受损蛋白质重新折叠,使蛋白质免受不可逆的热害损伤,增强植物在高温胁迫下的抗逆性。Yang等[7]和Chen等[8]观察到,雌蕊中具有较高BRs含量的水稻光温敏核不育系在开花期高温胁迫下所受的损伤较小,雌蕊受精能力更强;喷施外源BRs可显著提高水稻光温敏核不育系雌蕊中参与抗坏血酸―谷胱甘肽（AsA-GSH）循环酶的活性以及编码这些酶的基因的表达[28-29],显著降低其雌蕊中ACC和H2O2含量[8],增强其雌蕊抗氧化能力,进而有效减轻开花期高温胁迫对水稻光温敏核不育系雌蕊活性的负面影响（图1）。
BRs与JAs、ABA及乙烯之间在对高温胁迫下水稻光温敏核不育系雌蕊活性的调控上也可能存在交互作用。对开花期高温胁迫下的水稻光温敏核不育系同时喷施MeJA和BRs比单一喷施两者的某一种更能增强雌蕊活性（AsA含量更高,H2O2含量更低）,受精率与杂交制种产量也更高[7-8]。在甘蓝型油菜叶片上施用BRs可显著增加其内源ABA浓度并增强油菜植株对高温胁迫的耐受力[57]。在拟南芥和玉米植株上施用高浓度的ABA则显著降低其内源BRs水平,致使其对高温胁迫的耐受力变差[58-59]。此外,BRs和乙烯在对高温胁迫下水稻光温敏核不育系雌蕊活性的调控上存在明显的拮抗作用,即喷施外源BRs后可显著降低水稻光温敏核不育系雌蕊中ACC含量,导致乙烯生物合成受阻,进而显著降低其雌蕊中的ROS水平,有效减轻高温胁迫对水稻光温敏核不育系雌蕊受精的不利影响[7-8]（图1）。这些结果表明,提高水稻光温敏核不育系雌蕊中内源BRs的生物合成能力或降低乙烯的水平是增强高温胁迫下雌蕊活性与受精能力的一个重要途径。
3 高温胁迫对抽穗包颈的影响
对于常规水稻而言,在减数分裂期遭遇高温胁迫主要通过降低花药开裂率和花粉育性进而降低其结实率和产量[32],但水稻光温敏核不育系在温度高于24℃时,雄性器官（花粉）即表现不育。因此,对于水稻光温敏核不育系而言,抽穗前遭遇高温胁迫主要的危害是加剧了不育系的抽穗障碍（如包颈现象）。水稻细胞质雄性不育系和光温敏核不育系在抽穗时均普遍存在不同程度的包颈现象（稻穗不能完全抽出,穗基部颖花包裹在剑叶叶鞘中,无法接受外来花粉而受精结实）[60⇓-62]。水稻不育系抽穗包颈特性直接影响其异交受精率,是制约杂交种子生产的最大因素,也是评价不育系实用价值和经济价值的重要指标之一[63-64]。水稻不育系包穗是由于穗下倒1节间薄壁细胞（尤其是中部区段细胞）无法正常伸长与扩张,进而使穗下倒1节间缩短或退化缺失所致[65-66]。减数分裂期前后高温胁迫会进一步加剧水稻不育系抽穗包颈现象,进而严重阻碍其接受父本的花粉,显著降低不育系制种产量。但目前关于水稻不育系抽穗包颈性状（尤其在高温胁迫下）的机制研究[10]较少。
多种植物激素均可一定程度上影响水稻节间伸长,其中以GAs对水稻雄性不育系抽穗包颈的缓解作用最为明显[67⇓-69]。此外,BRs在促进茎鞘纵向伸长方面也发挥着至关重要的作用[10,56]。喷施外源BRs可不同程度地解除或缓解由于减数分裂期前后高温胁迫导致的雄性不育系水稻抽穗包颈现象[10]。但不同雄性不育水稻材料本身的抽穗包颈程度及其对激素的敏感性有较大差异,如中国育成的首个实用光温敏核不育系培矮64S不仅包颈严重,且对GAs钝感,制种田一般需要喷施450~750g/hm2 GAs才能解除其包颈性状,种子生产成本增加,且容易造成环境污染[70⇓⇓⇓-74]。近年来,隐性长节间基因eui（elongated upper most-internode）被发掘和鉴定[75⇓⇓-78]。eui种质能促进穗下倒1节间伸长,可在不影响不育系水稻花粉育性、半矮秆表型及杂种优势的前提下有效解除雄性不育系水稻的抽穗包颈性状,并能提高不育系的部分农艺性状（如剑叶会变长变宽,柱头外露率也有所提高等）[79]。因此,培育能够解除抽穗包颈性状的雄性不育系水稻是降低杂交稻制种成本和减轻高温胁迫的重要途径之一。
4 减轻水稻光温敏核不育系高温危害的调控措施
4.1 氮肥
氮素是影响水稻产量和品质的重要因素,适当增施氮肥可以降低植株冠层及穗部温度,提高水稻抗热害能力,使水稻结实率和千粒重增加[80-81]。高温胁迫下增施氮肥可提高水稻根系氧化活性和叶片光合作用,增强叶片氮代谢相关酶和籽粒蔗糖―淀粉转化相关酶的活性,减少植株体内活性氧的产生,增强植株活性[82-83]。在开花期增施氮肥通过降低水稻光温敏核不育系已开颖颖花温度和雌蕊活性氧水平,提高促生长类激素含量,增强碳氮代谢关键酶等生理活性,有效缓解开花期高温胁迫对水稻光温敏核不育系颖花开放和雌蕊活性的负面影响,从而提高不育系与恢复系杂交后的受精率、结实率和制种量[10]。因此,当开花期稻株含氮量低于1.8%时,适当增施氮肥是缓解开花期高温胁迫导致水稻光温敏核不育系颖花开放和雌蕊受精障碍的一个重要栽培措施[10]。
4.2 灌溉方式
传统观点[84-85]认为,水稻抽穗开花期遇高温,需要对稻田进行深层灌水以降低冠层温度,减轻高温对水稻的伤害。但有学者[86-87]观察到,高温对水稻的危害与水稻冠层相对湿度密切相关;在同一温度下,相对湿度越高,高温伤害越严重。轻干湿交替灌溉可以显著降低稻田的相对湿度,减轻高温对水稻的伤害,从而显著提高水稻的结实率、千粒重和产量。此外,轻干湿交替灌溉还可以增加水稻叶片中抗氧化物质和CTK含量,改善根系形态,提高根系代谢功能,协调地上部生长,使水稻在高温胁迫下保持正常的生理功能[86⇓-88]。Zhang等[89]观察到,稻穗发育期采用适度落干可显著提高水稻幼穗中BRs的生物合成,促进颖花分化并减少颖花退化,增加有效颖花数。这些结果表明,采用轻干湿交替灌溉可有效减轻高温胁迫对光温敏核不育系水稻的伤害,但其机理有待深入研究。
4.3 播期
4.4 喷施激素
4.5 分子育种
通过传统育种方法或基因工程技术提高水稻光温敏核不育系浆片中JAs或雌蕊等器官中BRs的生物合成与信号传导,进而培育出耐热性强的光温敏核不育系水稻品种,是缓解或解决高温胁迫对水稻光温敏核不育系造成危害的另一个有效措施。随着分子生物学与基因工程的飞速发展,水稻中已经克隆出JAs的生物合成关键基因[16]（如OsDAD1-3、OsLOX-RCI1、OsAOS1、OsAOC和OsOPR7）、信号转导关键基因[96]（如OsJAR1、OsCOI1b以及13个OsJAZs）、BRs生物合成关键基因[93]（如D11、D2和BRD2）和信号转导关键基因[97]（如OsBZR1）,并对这些基因的功能已有较为深入全面的认识。因此,上述基因均可直接加以利用,培育出耐热性强的光温敏核不育系水稻品种。
5 展望
目前,人们对高温胁迫导致水稻光温敏核不育系开颖与受精障碍的机理认识较少,仅有的研究或侧重于某个独立器官的性状变化,或侧重于某个单独激素的响应与作用,而缺乏对其系统的认识。因此,建议今后可从以下5个方面深入研究水稻光温敏核不育系开颖与雌蕊受精的高温危害。
（1）研究高温胁迫下水稻光温敏核不育系包颈特性的分子机制,阐明高温加剧不育系包颈程度的内在机理;重点研究GAs和BRs缓解或解除水稻光温敏核不育系包颈的机理,探明缓解高温下水稻光温敏核不育系包颈加剧的有效调控措施。
（2）研究高温胁迫下水稻光温敏核不育系根系形态生理特征与根系化学信号传递、植株地上部（茎、叶与穗）激素含量或比例的变化以及碳氮代谢特性等与光温敏核不育系水稻开颖与受精的内在联系。分别从植株、器官与细胞水平等不同层次上阐明高温胁迫下水稻光温敏核不育系开颖与雌蕊受精障碍的内在机理。
（3）结合采用激素相关水稻突变体或转基因材料,利用现代分子生物学的技术手段重点研究JAs和BRs的生物合成、信号转导及其与其他激素（特别是ABA与乙烯）调控高温胁迫下水稻光温敏核不育系开颖与雌蕊受精障碍的互作机制。
（4）研究氮、磷、钾等矿质营养元素以及水分灌溉和播期等栽培措施对缓解水稻光温敏核不育系高温危害的作用及其机理,并探明缓解高温对水稻光温敏核不育系危害的环境条件指标,提出缓解水稻光温敏核不育系高温危害的栽培调控途径和关键技术。
（5）使用常规育种方法、生物信息分析、高通量全基因组测序和蛋白质组学等技术挖掘调节水稻光温敏核不育系包穗、开颖和雌蕊活性的有利基因和分子标记,培育出耐热性强的光温敏核不育系水稻品种。
参考文献
Progress in super-hybrid rice breeding
DOI:10.1016/j.cj.2017.02.001 URL [本文引用: 2]
Physiological mechanism underlying the effect of high temperature during anthesis on spikelet-opening of photo-thermo-sensitive genic male sterile rice lines
DOI:10.1038/s41598-020-59183-0 URL [本文引用: 10]
Roles of jasmonates and brassinosteroids in rice responses to high temperature stress-A review
Brassinosteroids mediate the effect of high temperature during anthesis on the pistil activity of photo-thermosensitive genetic male-sterile rice lines
DOI:10.1016/j.cj.2020.07.001 URL [本文引用: 9]
Jasmonates alleviate spikelet-opening impairment caused by high temperature stress during anthesis of photo-thermo-sensitive genic male sterile rice lines
水稻颖花自然开放过程中茉莉酸(JA)生物合成的变化
DOI:10.3724/SP.J.1006.2012.01891
[本文引用: 8]
外源茉莉酸(JA)及其甲酯(MeJA)对水稻、小麦、黑麦和高粱等禾本科植物颖花开放具有强烈的诱导效应,然而内源JA是否参与颖花开放的调控目前还缺乏充分的证据。本研究应用高效液相色谱-串联质谱(HPLC-MS/MS)系统检测了粳稻武运粳7号和籼稻明恢63颖花自然开放过程中JA水平变化,并以实时定量反转录PCR (real-time RT-PCR)技术分析了武运粳7号颖花开放过程中JA生物合成途径关键基因表达变化。结果发现,水稻颖花JA水平的变化与开颖进程相一致。JA水平在上午颖花开颖前较平稳,开颖时急剧上升至峰值,闭颖后又下降。开颖时JA水平的峰值比开颖前1 h提高4~5倍。与JA水平变化相对应,催化JA生物合成途径关键步骤同工酶的编码基因OsDAD1-3、OsLOX-RCI1、OsAOS1、OsAOC和OsOPR7的表达在开颖时会有不同程度的上调,闭颖后又下调。同一稻穗上正在开放的颖花JA含量及上述JA生物合成途径基因的表达水平也比已开放和未开放的颖花高。颖花开放时JA水平及其生物合成基因表达的上升和闭颖后的下降有力地表明内源JA参与水稻颖花开放的调控。
Jasmonate signaling and manipulation by pathogens and insects
DOI:10.1093/jxb/erw478
PMID:28069779
[本文引用: 1]
Plants synthesize jasmonates (JAs) in response to developmental cues or environmental stresses, in order to coordinate plant growth, development or defense against pathogens and herbivores. Perception of pathogen or herbivore attack promotes synthesis of jasmonoyl-L-isoleucine (JA-Ile), which binds to the COI1-JAZ receptor, triggering the degradation of JAZ repressors and induction of transcriptional reprogramming associated with plant defense. Interestingly, some virulent pathogens have evolved various strategies to manipulate JA signaling to facilitate their exploitation of plant hosts. In this review, we focus on recent advances in understanding the mechanism underlying the enigmatic switch between transcriptional repression and hormone-dependent transcriptional activation of JA signaling. We also discuss various strategies used by pathogens and insects to manipulate JA signaling and how interfering with this could be used as a novel means of disease control.© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Jasmonic acid deficiency leads to scattered floret opening time in cytoplasmic male sterile rice Zhenshan 97A
DOI:10.1093/jxb/erx251
PMID:28981770
[本文引用: 6]
Cytoplasmic male sterile (CMS) rice has been widely used for hybrid rice seed production in China. However, CMS rice suffers from undesirable flowering habits including scattered floret opening time (FOT), which causes different FOTs among parental rice plants and greatly reduces hybrid rice seed production. Little is known about the mechanism of scattered FOT in CMS rice. Our results demonstrate that scattered FOT in CMS rice Zhenshan 97A (ZS97A) resulted from the lack of a driving force to open florets, which was directly caused by retarded lodicule expansion. Our results indicate that retarded lodicule expansion in ZS97A was caused by reduced water accumulation due to retarded accumulation of osmotic regulation substances (ORSs). Further, the retardation in accumulation of ORSs and water were caused by jasmonic acid (JA) deficiency, resulting from down-regulation of OsAOC expression. Applying JA restored scattered FOT in ZS97A by promoting ORS and water accumulation, and inducing the expansion of the lodicules. Taken together, JA deficiency inhibited lodicule expansion by retarding the accumulation of ORSs and water, leading to scattered FOT in CMS rice ZS97A.© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.
Exogenous jasmonic acid and cytokinin antagonistically regulate rice flag leaf senescence by mediating chlorophyll degradation,membrane deterioration,and senescence-associated genes expression
Jasmonate action in plant growth and development
DOI:10.1093/jxb/erw495
PMID:28158849
[本文引用: 1]
Phytohormones, including jasmonates (JAs), gibberellin, ethylene, abscisic acid, and auxin, integrate endogenous developmental cues with environmental signals to regulate plant growth, development, and defense. JAs are well- recognized lipid-derived stress hormones that regulate plant adaptations to biotic stresses, including herbivore attack and pathogen infection, as well as abiotic stresses, including wounding, ozone, and ultraviolet radiation. An increasing number of studies have shown that JAs also have functions in a remarkable number of plant developmental events, including primary root growth, reproductive development, and leaf senescence. Since the 1980s, details of the JA biosynthesis pathway, signaling pathway, and crosstalk during plant growth and development have been elucidated. Here, we summarize recent advances and give an updated overview of JA action and crosstalk in plant growth and development.© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Arabidopsis AtMYC2 (bHLH) and AtMYB2 (MYB) function as transcriptional activators in abscisic acid signaling
DOI:10.1105/tpc.006130 URL [本文引用: 4]
Accumulation of jasmonate,abscisic acid,specific transcripts and proteins in osmotically stressed barley leaf segments
Heat shock factors in rice (Oryza sativa L.):genome-wide expression analysis during reproductive development and abiotic stress
DOI:10.1007/s00438-011-0638-8
PMID:21792744
[本文引用: 4]
Plants respond to heat stress by enhancing the expression of genes encoding heat shock protein (HSPs) genes through activation of heat shock factors (HSFs) which interact with heat shock elements present in the promoter of HSP genes. Plant HSFs have been divided into three conserved classes viz A, B and C. In the present study, a detailed analysis has been done of all rice HSFs, along with their spliced variants. Their chromosomal localization reveals that six HSFs are segmentally duplicated and four pairs of these segmentally duplicated HSF encoding genes show pseudo-functionalization. Expression profiling through microarray and quantitative real-time PCR showed that eight OsHsfs express at a higher level during seed development, while six HSFs are up-regulated in all the abiotic stresses studied. The expression of OsHsfA2a gene in particular was greatly stimulated by heat stress in both root and shoot tissues and also during panicle and seed development. OsHsfA3 was found more responsive to cold and drought stress, while OsHsfA7 and OsHsfA9 showed developing seed-specific expression. This study also revealed that spliced variants generally accumulated at a higher level in all the tissues examined. Different hormones/elicitors like ABA, brassinosteroids and salicylic acid also alter OsHsf gene expression. Calcium in combination with heat stress elevated further the level of HSF transcripts. Expression analysis by both microarray and real-time RT-PCR revealed a unique stable constitutive expression of OsHsfA1 across all the tissues and stresses. A detailed in silico analysis involving identification of unidentified domains has been done by MEME-motif tool in their full-length proteins as well as in DNA-binding domains. Analysis of 1 kb putative promoter region revealed presence of tissue-specific, abiotic stress and hormone-related cis-acting elements, correlating with expression under stress conditions.
Physiological and molecular effects of 24-epibrassinolide,a brassinosteroid on thermotolerance of tomato
DOI:10.1007/s10725-005-3252-0 URL [本文引用: 4]
Brassinosteroids alleviate high-temperature injury in ficus concinna seedlings via maintaining higher antioxidant defence and glyoxalase systems
DOI:10.1093/oxfordjournals.aob.a088522 URL [本文引用: 4]
Brassinosteroids attenuate moderate high temperature-caused decline in tea quality by enhancing theanine biosynthesis in Camellia sinensis L.
DOI:10.3389/fpls.2018.01016 URL [本文引用: 4]
Can hot-water emasculation be applied to artificial hybridization of Indica-type cambodian rice?
DOI:10.1626/pps.11.132 URL [本文引用: 1]
减数分裂期高温胁迫对耐热性不同水稻品种产量的影响及其生理原因
DOI:10.3724/SP.J.1006.2008.02134
[本文引用: 2]
以两个耐热性不同的籼稻品种为材料,在减数分裂期进行高温(白天温度>35℃)处理,以同期自然温度(白天温度<33℃)为对照,研究减数分裂期高温对产量的影响及其生理机制。结果表明,高温处理与对照相比,显著降低了热敏感品种双桂1号的花药开裂率及花粉育性,对耐热品种黄华占影响较小；明显降低了每穗颖花数、结实率和粒重,从而使产量显著下降,其中耐热品种下降幅度小于热敏感品种；热敏感品种粒宽显著缩短,长宽比显著增大,而对耐热型品种影响不大；明显降低了水稻的根系活力和幼穗的核糖核酸(RNA)含量,显著增加了叶片丙二醛(MDA)含量和幼穗的乙烯释放速率,热敏感品种变化幅度大于耐热品种；显著增加了耐热品种叶片的抗氧化酶活性,对热敏感品种无显著影响。总之,根系活力和抗氧化保护系统能力强、RNA含量高、MDA含量低及乙烯合成少是耐热性品种在高温胁迫下保持较高产量的重要生理原因。
Short-term high temperature growth conditions during vegetative-to-reproductive phase transition irreversibly compromise cell wall invertase-mediated sucrose catalysis and microspore meiosis in grain sorghum (Sorghum bicolor)
DOI:10.1016/j.jplph.2009.11.007
PMID:20044168
[本文引用: 1]
Grain sorghum (Sorghum bicolor) crop yield is significantly compromised by high temperature stress-induced male sterility, and is attributed to reduced cell wall invertase (CWI)-mediated sucrose hydrolysis in microspores and anthers leading to altered carbohydrate metabolism and starch deficiency in pollen (Jain et al., 2007). Sorghum plants were grown under season-long ambient (30/20 degrees C day-time maximum/night-time minimum) or high temperature stress (HS, 36/26 degrees C) environments, or reciprocally transferred for 5-10 days between either temperature regimens through panicle and microspore developmental stages. Quantitative RT-PCR analyses for CWI gene SbIncw1, plasma membrane H(+)-ATPase (Mha1) and sugar transporter proteins (OsSUT3 and OsMST7 homologs in sorghum), starch deficiency and pollen sterility data are presented to confirm HS-sensitivity of pre- and post-meiotic stages of sorghum microsporogenesis. Heat stress-induced reduction in Incw transcriptional activity during microspore meiosis was irreversible despite return of optimal growth temperature conditions through further reproductive development.Copyright 2009 Elsevier GmbH. All rights reserved.
Possible correlation between high temperature-induced floret sterility and endogenous levels of IAA,GAs and ABA in rice (Oryza sativa L.)
DOI:10.1007/s10725-007-9225-8 URL [本文引用: 1]
Temperature stress and plant sexual reproduction:uncovering the weakest links
DOI:10.1093/jxb/erq053 URL [本文引用: 1]
Peptide signalling during the pollen tube journey and double fertilization
DOI:10.1093/jxb/erv275
PMID:26068467
[本文引用: 1]
Flowering seed plants (angiosperms) have evolved unique ways to protect their gametes from pathogen attack and from drying out. The female gametes (egg and central cell) are deeply embedded in the maternal tissues of the ovule inside the ovary, while the male gametes (sperm cells) are enclosed in the vegetative pollen tube cell. After germination of the pollen tube at the surface of papilla cells of the stigma the two immobile sperm cells are transported deep inside the sporophytic maternal tissues to be released inside the ovule for double fertilization. Angiosperms have evolved a number of hurdles along the pollen tube journey to prevent inbreeding and fertilization by alien sperm cells, and to maximize reproductive success. These pre-zygotic hybridization barriers require intensive communication between the male and female reproductive cells and the necessity to distinguish self from non-self interaction partners. General molecules such as nitric oxide (NO) or gamma-aminobutyric acid (GABA) therefore appear to play only a minor role in these species-specific communication events. The past 20 years have shown that highly polymorphic peptides play a leading role in all communication steps along the pollen tube pathway and fertilization. Here we review our current understanding of the role of peptides during reproduction with a focus on peptide signalling during self-incompatibility, pollen tube growth and guidance as well as sperm reception and gamete activation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Response of floret fertility and individual grain weight of wheat to high temperature stress:Sensitive stages and thresholds for temperature and duration
DOI:10.1071/FP14061 URL [本文引用: 1]
Floral traits to enhance outcrossing for higher hybrid seed production in rice:present status and future prospects
DOI:10.1007/s10681-014-1251-9 URL [本文引用: 1]
Experimental insights on the function of ancillary pollen and stigma polymorphisms in plants with heteromorphic incompatibility
DOI:10.1111/evo.13082 URL [本文引用: 1]
Genome-wide association analyses reveal the genetic basis of stigma exsertion in rice
DOI:S1674-2052(17)30002-3
PMID:28110091
[本文引用: 1]
Stigma exsertion, a key determinant of the rice mating system, greatly contributes to the application of heterosis in rice. Although a few quantitative trait loci associated with stigma exsertion have been fine mapped or cloned, the underlying genetic architecture remains unclear. We performed a genome-wide association study on stigma exsertion and related floral traits using 6.5 million SNPs characterized in 533 diverse accessions of Oryza sativa. We identified 23 genomic loci that are significantly associated with stigma exsertion and related traits, three of which are co-localized with three major grain size genes GS3, GW5, and GW2. Further analyses indicated that these three genes affected the stigma exsertion by controlling the size and shape of the spikelet and stigma. Combinations of GS3 and GW5 largely defined the levels of stigma exsertion and related traits. Selections of these two genes resulted in specific distributions of floral traits among subpopulations of O. sativa. The low stigma exsertion combination gw5GS3 existed in half of the cultivated rice varieties; therefore, introducing the GW5gs3 combination into male sterile lines is of high potential for improving the seed production of hybrid rice.Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.
qSE7 is a major quantitative trait locus (QTL) influencing stigma exsertion rate in rice (Oryza sativa L)
DOI:10.1038/s41598-018-32629-2 URL [本文引用: 1]
Patterns of ROS accumulation in the stigmas of angiosperms and visions into their multi-functionality in Plant Reproduction
Hypoxia triggers meiotic fate acquisition in maize
DOI:10.1126/science.1220080
PMID:22822150
[本文引用: 1]
Evidence from confocal microscopic reconstruction of maize anther development in fertile, mac1 (excess germ cells), and msca1 (no germ cells) flowers indicates that the male germ line is multiclonal and uses the MAC1 protein to organize the somatic niche. Furthermore, we identified redox status as a determinant of germ cell fate, defining a mechanism distinct from the animal germ cell lineage. Decreasing oxygen or H(2)O(2) increases germ cell numbers, stimulates superficial germ cell formation, and rescues germinal differentiation in msca1 flowers. Conversely, oxidizing environments inhibit germ cell specification and cause ectopic differentiation in deeper tissues. We propose that hypoxia, arising naturally within growing anther tissue, acts as a positional cue to set germ cell fate.
Heat stress induces spikelet sterility in rice at anthesis through inhibition of pollen tube elongation interfering with auxin homeostasis in pollinated pistils
DOI:10.1186/s12284-018-0206-5 URL [本文引用: 2]
Heat stress transcription factor OsSPL 7 plays a critical role in reactive oxygen species balance and stress responses in rice
DOI:10.1016/j.plantsci.2019.110273 URL [本文引用: 1]
Keeping up with the RALFs:how these small peptides control pollen-pistil interactions in Arabidopsis
DOI:10.1111/nph.16817 URL [本文引用: 1]
Targeting of pollen tubes to ovules is dependent on nitric oxide(NO) signaling
DOI:10.1093/mp/ssn034 URL [本文引用: 1]
A fruitful journey:pollen tube navigation from germination to fertilization
DOI:10.1146/annurev-arplant-050718-100133 URL [本文引用: 1]
How does timing,duration,and severity of heat stress influence pollen-pistil interactions in angiosperms
DOI:10.4161/psb.6.7.15315
PMID:21628998
[本文引用: 1]
Reproductive development in sexual plants is substantially more sensitive to high temperature stress than vegetative development, resulting in negative implications for food and fiber production under the moderate temperature increases projected to result from global climate change. High temperature exposure either during early pollen development or during the progamic phase of pollen development will negatively impact pollen performance and reproductive output; both phases of pollen development are considered exceptionally sensitive to moderate heat stress. However, moderately elevated temperatures either before or during the progamic phase can limit fertilization by negatively impacting important pollen pistil interactions required for successful pollen tube growth toward the ovules. This minireview identifies the impacts of heat stress on pollen-pistil interactions and sexual reproduction in angiosperms. A special emphasis is placed on the biochemical response of the pistil to moderately high temperature and the resultant influence on in vivo pollen performance and fertilization.
Acid invertase confers heat tolerance in rice plants by maintaining energy homoeostasis of spikelets
DOI:10.1111/pce.13733 URL [本文引用: 1]
The neglected other half‐role of the pistil in plant heat stress responses
DOI:10.1111/pce.14067 URL [本文引用: 2]
The physiological and molecular mechanism of brassinosteroid in response to stress:a review
DOI:10.1186/s40659-018-0195-2
PMID:30419959
[本文引用: 1]
The negative effects of environmental stresses, such as low temperature, high temperature, salinity, drought, heavy metal stress, and biotic stress significantly decrease crop productivity. Plant hormones are currently being used to induce stress tolerance in a variety of plants. Brassinosteroids (commonly known as BR) are a group of phytohormones that regulate a wide range of biological processes that lead to tolerance of various stresses in plants. BR stimulate BRASSINAZOLE RESISTANCE 1 (BZR1)/BRI1-EMS SUPPRESSOR 1 (BES1), transcription factors that activate thousands of BR-targeted genes. BR regulate antioxidant enzyme activities, chlorophyll contents, photosynthetic capacity, and carbohydrate metabolism to increase plant growth under stress. Mutants with BR defects have shortened root and shoot developments. Exogenous BR application increases the biosynthesis of endogenous hormones such as indole-3-acetic acid, abscisic acid, jasmonic acid, zeatin riboside, brassinosteroids (BR), and isopentenyl adenosine, and gibberellin (GA) and regulates signal transduction pathways to stimulate stress tolerance. This review will describe advancements in knowledge of BR and their roles in response to different stress conditions in plants.
Brassinosteroids function in spikelet differentiation and degeneration in rice
DOI:10.1111/jipb.12722 URL [本文引用: 1]
Brassinosteroids mediate the effect of soil-drying during meiosis on spikelet degeneration in rice
DOI:10.1016/j.envexpbot.2019.103887 URL [本文引用: 1]
Abscisic acid negatively modulates heat tolerance in rolled leaf rice by increasing leaf temperature and regulating energy homeostasis
DOI:10.1186/s12284-020-00379-3 URL [本文引用: 2]
A rapid effect of applied brassinolide on abscisic acid concentrations in Brassica napus leaf tissue subjected to short-term heat stress
DOI:10.1007/s10725-008-9276-5 URL [本文引用: 1]
Identification and characterization of the BZR transcription factor family and its expression in response to abiotic stresses in Zea mays L.
DOI:10.1007/s10725-017-0350-8 URL [本文引用: 1]
Brassinosteroid-mediated stress tolerance in Arabidopsis shows interactions with abscisic acid,ethylene and salicylic acid pathways
DOI:10.1186/1471-2229-10-151 URL [本文引用: 1]
Interaction between the eui gene and thermo-sensitive genic male sterility in rice
DOI:10.1007/s10681-008-9657-x URL [本文引用: 1]
Decreased panicle-derived indole-3-acetic acid reduces gibberellin A 1 level in the uppermost internode,causing panicle enclosure in male sterile rice Zhenshan 97A
DOI:10.1093/jxb/erm077 URL [本文引用: 1]
High temperature stress effects on pollens of rice (Oryza sativa L.) genotypes
DOI:10.1016/j.envexpbot.2014.01.004 URL [本文引用: 1]
Spikelet proteomic response to combined water deficit and heat stress in rice (Oryza sativa cv. N22)
DOI:10.1007/s12284-011-9059-x URL [本文引用: 1]
Genetic analysis and fine mapping of an enclosed panicle mutant esp2 in rice (Oryza sativa L.)
DOI:10.1007/s11434-011-4552-9 URL [本文引用: 1]
A fourth genetic element to facilitate hybrid cereal productions recessive tall in rice
DOI:10.2135/cropsci1981.0011183X002100030005x URL [本文引用: 1]
Fine mapping and in silico isolation of the EUI1 gene controlling upper internode elongation in rice
Rice HOX12 regulates panicle exsertion by directly modulating the expression of ELONGATED UPPERMOST INTERNODE1
DOI:10.1105/tpc.15.01021 URL [本文引用: 1]
穗肥施量对水稻植株形态、群体生态及穗叶温度的影响
DOI:10.3724/SP.J.1006.2008.02176
[本文引用: 1]
以2个籼、粳稻品种为材料,设置高、中、低3个穗肥处理,以空白为对照,构建不同的群体结构,研究穗肥施量对植株形态和群体生态及穗叶温度的影响。结果表明,穗肥施量对穗长、穗弯曲度、叶长和叶角有明显影响；不同穗肥处理群体内部温度、湿度、光照强度和CO2浓度等微气象因子具有一定差异,中肥处理具有良好的群体微气象环境；此外,中肥处理群体具有适宜的LAI、净光合速率和蒸腾速率,冠层温度较低；施肥水平显著影响植株器官的温度,穗叶的温度随穗肥施量的增加而降低,中肥与高肥处理植株穗叶的温度差异不显著,但与低肥和空白处理差异显著。研究结果说明通过优化田间管理如合理的施肥来构建良好的群体,对降低植株穗叶和冠层温度以提高水稻抗热害能力效果显著。
High nitrogen levels alleviate yield loss of super hybrid rice caused by high temperatures during the flowering stage
DOI:10.3389/fpls.2019.00357
PMID:30972091
[本文引用: 1]
The effect of high temperatures on rice production has attracted considerable research attention. It is not clear, however, whether nitrogen (N) management can be used to alleviate the damaging effects of high temperatures on flowering in rice. In this study, we compared the yields of five elite super hybrid rice varieties and examined their heat tolerance under four N treatments in two seasons with contrasting temperatures at flowering: 2015 (normal temperature) and 2016 (high temperature). The average daily temperature during the flowering stage in 2016 was 31.1°C, which was 4.5°C higher than that in 2015. There was a significant positive correlation between grain yield and N level ( = 0.42, < 0.01). However, mean grain yield of the five rice varieties in 2015 was 10.5% higher than that in 2016. High N levels reduced yield losses in plants exposed to high temperature in 2016. The mean seed-set percentage in 2016 was 13.0% lower than that in 2015 at higher N levels, but spikelets per panicle increased by 7.6% at higher N levels compared with lower N levels. Higher N levels reduced the number of degenerated spikelets under high temperatures. Spikelets per panicle and N treatment level were positively correlated at high temperatures ( = 0.32, < 0.05). These results confirmed that increasing N application could alleviate yield losses caused by high temperatures in super hybrid rice during the flowering stage.
Impact of humidity on temperature-induced grain sterility in rice (Oryza sativa L.)
DOI:10.1111/j.1439-037X.2008.00293.x URL [本文引用: 1]
Role of brassinosteroids in rice spikelet differentiation and degeneration under soil-drying during panicle development
DOI:10.1186/s12870-019-2025-2 URL [本文引用: 1]
Shifting planting date of Boro rice as a climate change adaptation strategy to reduce water use
DOI:10.1016/j.agsy.2018.11.006
[本文引用: 1]
Suitable adaptation strategies for dry season Boro rice cultivation under future climate change scenarios are important for future food security in Bangladesh. This study assessed the effect of shifting trans- /planting date of dry season Boro rice as an adaptation strategy, with focus on water requirements under future climate scenarios. Potential crop water requirement, effective rainfall and irrigation requirement to satisfy crop evapo-transpiration of Boro rice were estimated using CropWat 8.0 for early, normal and late planting dates for 2050s and 2080s. Future climate scenarios were constructed using five global circulation model (GCM) outputs for RCP 4.5 and 8.5 by statistical downscaling and bias correction. Number of days exceeding the threshold temperatures (maximum of 35 degrees C and minimum of 25 degrees C) was counted for critical period of Boro rice to understand compatibility of the changed planting dates. Results indicate that late planting can substantially reduce irrigation demand by increasing rainfall availability during Boro growth duration, but the option is very limited due to both day- and night-time heat stress. An early planting, on the other hand, accounts for high water demand but ensures suitable temperature during the critical growth stages of the crop. The normal planting dates show the possibility of day-time heat stress. So, late planting of temperature-tolerant cultivars or early planting of high-yielding varieties would be recommended based on local water availability. However, adjustment of the planting date is currently limited because high temperature-tolerant cultivars are not available in the study region.
Adaptation of paddy rice in China to climate change:The effects of shifting sowing date on yield and irrigation water requirement
DOI:10.1016/j.agwat.2019.105890 URL [本文引用: 2]
Crop season planning tool:adjusting sowing decisions to reduce the risk of extreme weather events
DOI:10.1016/j.compag.2018.11.013
[本文引用: 1]
Frost, extreme high temperatures, dry spells, and other weather extremes influence crop development, often causing major variations in yield from one season to the next. Selected growth stages such as flowering and grain filling are particularly sensitive to temperature and/or precipitation extremes and farmers are often unable to manage this risk. Crop simulation models have matured into powerful tools for identifying strategies in fully utilizing scarce natural resources under variable climate conditions. However, the use of crop models often requires expert knowledge and an extensive number of input datasets. Combining the power of Internet, computing technology, and web-based decision-support tools is becoming increasingly popular in situations where these requirements cannot be met. The objective of this study is to develop a simple decision-support tool that combines freely available information with the functionality of complex crop models in a user friendly interface for real-time assessment of soil, plant, and weather information. The resulting tool is intended to be used ahead of the growing season by producers, and it enables the estimation and minimization of the likelihood of extreme weather events during critical stages of crop development.
Rice spikelet formation inhibition caused by decreased sugar utilization under high temperature is associated with brassinolide decomposition
DOI:10.1016/j.envexpbot.2021.104585 URL [本文引用: 2]
播期对南方双季晚籼稻温光资源利用、产量及品质形成的影响
DOI:10.3969/j.issn.1006-8082.2021.05.025
[本文引用: 2]
调整播期可以改变水稻生长发育中的环境气候条件,对于充分利用自然资源、调节水稻生育进程及提升产量和品质具有重要意义。为明确南方双季晚籼稻优质丰产与温光资源相适应的播种期,本研究选用万象优华占、象牙香珍和美香占2号等3个晚籼稻品种为试验材料,设置6月10日、6月20日、6月30日共3个播期,研究播期对双季晚籼稻品种温光资源利用、产量及稻米品质的影响。结果表明,随着播期推迟,供试品种在不同生育阶段日均温度和有效积温、全生育期和齐穗至成熟期阶段的日照时数均呈递减趋势,而全生育期天数无明显变化;产量以6月20日播种的最高,早播（6月10日）会导致显著减产,而晚播（6月30日）虽然也会导致减产,但差异不显著;随播期推迟,晚籼稻品种加工品质、外观品质和蒸煮品质变优,但不利于改善食味品质,对营养品质无显著影响。在南方双季晚籼稻实际生产中,不建议早播,应根据品种不同进行适期播种或适当晚播,能使水稻更合理有效地利用温光资源,有利于协调水稻高产和品质提升。
播期对南方优质晚粳稻产量及稻米品质的调控效应研究
DOI:10.3969/j.issn.1006-8082.2018.05.012
[本文引用: 1]
近年来,“籼改粳”在江西等南方双季稻区发展较快,关于双季晚粳稻高产品种及其配套栽培技术的研究也有了较多的报道,但关于优质晚粳稻产量及品质的播期调控效应仍不清楚。本研究以南方优质晚粳稻品种甬优1538为材料,通过开展分期播种试验,研究了不同播期对优质晚粳稻产量和米质变化的影响。结果表明,随着播期的推迟,甬优1538的有效穗数呈增加趋势,每穗粒数和千粒重先增后降,而结实率呈现降低趋势,最终产量呈先增后降的趋势,以播期为6月25日时产量最高。随着播期的推迟,甬优1538的加工品质、外观品质及蒸煮与食味品质均变劣,而营养品质变化趋势因指标而异,峰值粘度、热浆粘度、冷胶粘度和崩解值呈逐渐降低趋势,而回复值和消减值呈逐渐增加趋势。可见,在南方双季稻区晚粳生产中,适当早播有利于同步实现高产和优质。
Diversification of plant agronomic traits by genome editing of brassinosteroid signaling family genes in rice
DOI:10.1093/plphys/kiab394 URL [本文引用: 1]
