Cytoplasmic male sterility(CMS), a maternally inherited trait, provides a promising means to harness yield gains associated with hybrid vigor. In pigeonpea [Cajanus cajan (L.) Huth], nine types of sterility-inducing cytoplasm have been reported, of which A₂ and A₄ have been successfully deployed in hybrid breeding. Unfortunately, molecular mechanism of the CMS trait is poorly understood because of limited research invested. More recently, an association between a mitochondrial gene (nad7) and A₄-CMS has been demonstrated in pigeonpea; however, the mechanism underlying A₂-CMS still remains obscure. The current investigation aimed to analyze the differences in A₂-CMS line (ICPL 88039A) and its isogenic maintainer line (ICPL 88039B) at transcriptome level using next-generation sequencing. Gene expression profiling uncovered a set of 505 genes that showed altered expression in response to CMS, of which, 412 genes were upregulated while 93 were downregulated in the fertile maintainer line vs. the CMS line. Further, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) network analyses revealed association of CMS in pigeonpea with four major pathways: glucose and lipid metabolism, ATP production, pollen development and pollen tube growth, and reactive oxygen species (ROS) scavenging. Patterns of digital gene expression were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) of six candidate genes. This study elucidates candidate genes and metabolic pathways having potential associations with pollen development and male sterility in pigeonpea A₂-CMS. New insights on molecular mechanism of CMS trait in pigeonpea will be helpful to accelerate heterosis utilization for enhancing productivity gains in pigeonpea.

中文翻译：

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A2细胞质条件下雄性不育木豆的全局基因表达分析

细胞质雄性不育（CMS）是一种母系遗传性状，为利用与杂交优势相关的产量增加提供了一种有希望的方法。在木豆[ Cajanus cajan (L.) Huth]中，已报道了9种诱导不育的细胞质，其中A ₂和A ₄已成功应用于杂交育种。不幸的是，由于有限的研究投入，CMS 性状的分子机制知之甚少。最近，在木豆中证实了线粒体基因（nad7）和 A ₄ -CMS 之间的关联。_{然而，A 2} -CMS背后的机制仍然模糊不清。目前的调查旨在分析 A _2的差异-CMS 系 (ICPL 88039A) 及其同基因维持系 (ICPL 88039B) 使用下一代测序在转录组水平上进行。基因表达谱揭示了一组 505 个基因，这些基因在响应 CMS 时表现出改变的表达，其中 412 个基因上调，而 93 个基因在可育维持系与 CMS 系中下调。此外，基因本体论 (GO)、京都基因和基因组百科全书 (KEGG) 和蛋白质-蛋白质相互作用 (PPI) 网络分析揭示木豆中的 CMS 与四个主要途径相关：葡萄糖和脂质代谢、ATP 产生、花粉发育和花粉管生长和活性氧（ROS）清除。数字基因表达模式通过六个候选基因的定量实时聚合酶链反应 (qRT-PCR) 得到证实。₂ -CMS。对木豆 CMS 性状分子机制的新认识将有助于加速利用杂种优势来提高木豆的生产力。