College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China.
College of Agriculture, Guangxi University, Nanning 530004, Guangxi, China.
Int J Mol Sci. 2019 Nov 5;20(21):5515. doi: 10.3390/ijms20215515.
Cytoplasmic male sterility (CMS) is a maternally inherited trait used for hybrid production in plants, a novel kenaf CMS line 722HA was derived from the thermo-sensitive male-sterile mutant 'HMS' by recurrent backcrossing with 722HB. The line 722HA has great potential for hybrid breeding in kenaf. However, the underlying molecular mechanism that controls pollen abortion in 722HA remains unclear, thus limiting the full utilization of this line. To understand the possible mechanism governing pollen abortion in 722HA, cytological, transcriptomic, and biochemical analyses were carried out to compare the CMS line 722HA and its maintainer line 722HB. Cytological observations of the microspore development revealed premature degradation of the tapetum at the mononuclear stage, which resulted in pollen dysfunction. The k-means clustering analysis of differentially expressed genes (DEGs) revealed that these genes are related to processes associated with the accumulation of reactive oxygen species (ROS), including electron transport chain, FF-ATPase proton transport, positive regulation of superoxide dismutase (SOD), hydrogen peroxide catabolic, and oxidation-reduction. Biochemical analysis indicated that ROS-scavenging capability was lower in 722HA than in 722HB, resulting in an accumulation of excess ROS, which is consistent with the transcriptome results. Taken together, these results demonstrate that excessive ROS accumulation may affect the normal development of microspores. Our study provides new insight into the molecular mechanism of pollen abortion in 722HA and will promote further studies of kenaf hybrids.
细胞质雄性不育（CMS）是一种母系遗传的特性，用于植物的杂种生产。新型麻 CMS 品系 722HA 是通过与 722HB 反复回交，从热敏雄性不育突变体 'HMS' 中衍生而来。该品系 722HA 在麻杂交种选育方面具有巨大潜力。然而，控制 722HA 花粉败育的潜在分子机制尚不清楚，这限制了该品系的充分利用。为了了解控制 722HA 花粉败育的可能机制，对 CMS 品系 722HA 及其保持系 722HB 进行了细胞学、转录组和生化分析。对小孢子发育的细胞学观察表明，绒毡层在单核期过早降解，导致花粉功能障碍。差异表达基因（DEGs）的 k-means 聚类分析表明，这些基因与与活性氧（ROS）积累相关的过程有关，包括电子传递链、FF-ATPase 质子转运、超氧化物歧化酶（SOD）的正调控、过氧化氢分解和氧化还原。生化分析表明，722HA 的 ROS 清除能力低于 722HB，导致过量 ROS 的积累，这与转录组结果一致。综上所述，这些结果表明过量的 ROS 积累可能会影响小孢子的正常发育。我们的研究为 722HA 花粉败育的分子机制提供了新的见解，并将促进对麻杂种的进一步研究。
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