Lei Xiaoning, Liu Bing
School of Public Health, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Laboratory of Health Technology Assessment, Fudan University, Shanghai, China.
Hubei Provincial Key Laboratory for Protection and Application of Special Plants in Wuling Area of China, College of Life Sciences, South-Central University for Nationalities, Wuhan, China.
Front Plant Sci. 2020 Jan 16;10:1667. doi: 10.3389/fpls.2019.01667. eCollection 2019.
In higher plants, male meiosis is a key process during microsporogenesis and is crucial for male fertility and seed set. Meiosis involves a highly dynamic organization of chromosomes and cytoskeleton and specifically takes place within sexual cells. However, studies in multiple plant species have suggested that the normal development of tapetum, the somatic cell layer surrounding the developing male meiocytes, is indispensable for the completion of the male meiotic cell cycle. Disrupted tapetum development causes alterations in the expression of a large range of genes involved in male reproduction. Moreover, recent experiments suggest that small RNAs (sRNAs) present in the anthers, including microRNAs (miRNAs) and phased, secondary, small interfering RNAs (phasiRNAs), play a potential but important role in controlling male meiosis, either by influencing the expression of meiotic genes in the meiocytes or through other unclear mechanisms, supporting the hypothesis that male meiosis is non-cell autonomously regulated. In this mini review, we summarize the recorded meiotic defects that occur in plants with defective tapetum development in both Arabidopsis and crops. Thereafter, we outline the latest understanding on the molecular mechanisms that potentially underpin the tapetum-dependent regulation of male meiosis, and we especially discuss the regulatory role of sRNAs. At the end, we propose several outstanding questions that should be addressed in future studies.
在高等植物中，雄配子减数分裂是小孢子发生过程中的关键环节，对雄性育性和结实率至关重要。减数分裂涉及染色体和细胞骨架的高度动态组织，且专门发生在性细胞内。然而，对多种植物的研究表明，绒毡层（围绕发育中的雄配子母细胞的体细胞层）的正常发育对于雄配子减数分裂细胞周期的完成是不可或缺的。绒毡层发育异常会导致大量参与雄性生殖的基因表达发生改变。此外，最近的实验表明，花药中存在的小RNA（sRNA），包括微小RNA（miRNA）和阶段性、二级、小干扰RNA（phasiRNA），在控制雄配子减数分裂中发挥着潜在但重要的作用，其作用方式可能是影响配子母细胞中减数分裂基因的表达，或通过其他尚不清楚的机制，这支持了雄配子减数分裂是非细胞自主调控的假说。在这篇小型综述中，我们总结了拟南芥和农作物中绒毡层发育缺陷的植物所出现的减数分裂缺陷记录。此后，我们概述了对潜在支撑绒毡层依赖性雄配子减数分裂调控的分子机制的最新认识，特别讨论了sRNA的调控作用。最后，我们提出了几个未来研究中应解决的突出问题。
