ICAR-National Institute for Plant Biotechnology, New Delhi, 110012, India.
Centre for Medical Biotechnology, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, 201313, India.
Plant Cell Rep. 2021 May;40(5):881-898. doi: 10.1007/s00299-021-02686-5. Epub 2021 Apr 10.
Comparative transcriptome analyses accompanied by biochemical assays revealed high variability in heat stress response in Cajanus species. Among the studied species, C. scarabaeoides was the most thermotolerant followed by C. cajanifolius, C. cajan, and C. acutifolius. Pigeonpea is one of the climate-resilient grain legumes. Though the optimum temperature for cultivated pigeonpea is ~ 25-35 °C, its wild relatives grow in temperatures ranging between 18 and 45 °C. To gain insight into molecular mechanisms responsible for the heat stress tolerance in pigeonpea, we conducted time-series transcriptome analysis of one pigeonpea cultivar (Cajanus cajan) and two wild relatives, Cajanus acutifolius, and Cajanus scarabaeoides subjected to heat stress at 42 ± 2 ºC for 30 min and 3 h. A total of 9521, 12,447, and 5282 identified transcripts were differentially expressed in C. cajan, C. acutifolius, and C. scarabaeoides, respectively. In this study, we observed that a significant number of genes undergo alternative splicing in a species-specific pattern during heat stress. Gene expression profiling analysis, histochemical assay, chlorophyll content, and electrolyte leakage assay showed that C. scarabaeoides has adaptive features for heat stress tolerance. The gene set enrichment analyses of differentially expressed genes in these Cajanus species during heat stress revealed that oxidoreductase activity, transcription factor activity, oxygen-evolving complex, photosystem-II, thylakoid, phenylpropanoid biosynthetic process, secondary metabolic process, and flavonoid biosynthetic process were highly affected. The histochemical assay showed more lipid peroxidation in C. acutifolius compared to other Cajanus species inferring the presence of higher quantities of polyunsaturated fatty acids in the plasma membrane which might have led to severe damage of membrane-bound organelles like chloroplast, and high electrolyte leakage during heat stress. This study paves the way for the identification of candidate genes, which can be useful for the development of thermo-tolerant pigeonpea cultivars.
通过比较转录组分析和生化分析，揭示了豇豆属植物在热应激反应方面的高度变异性。在所研究的物种中，C. scarabaeoides 是最耐热的，其次是 C. cajanifolius、C. cajan 和 C. acutifolius。兵豆是一种具有气候适应能力的粮食豆类作物。虽然栽培兵豆的最适温度约为 25-35°C，但它的野生亲缘种在 18-45°C 的温度下生长。为了深入了解兵豆耐热的分子机制，我们对一个栽培种（Cajanus cajan）和两个野生亲缘种 Cajanus acutifolius 和 Cajanus scarabaeoides 进行了时间序列转录组分析，将它们在 42±2°C 下热应激 30 分钟和 3 小时。在 C. cajan、C. acutifolius 和 C. scarabaeoides 中，分别有 9521、12447 和 5282 个鉴定的转录本差异表达。在这项研究中，我们观察到，在热应激过程中，大量基因以物种特异性的方式发生可变剪接。基因表达谱分析、组织化学分析、叶绿素含量和电解质泄漏分析表明，C. scarabaeoides 具有适应热应激的特征。对这些豇豆属物种在热应激过程中差异表达基因的基因集富集分析表明，氧化还原酶活性、转录因子活性、氧释放复合物、光系统-II、类囊体、苯丙烷生物合成过程、次生代谢过程和类黄酮生物合成过程受到高度影响。组织化学分析表明，C. acutifolius 中的脂质过氧化程度高于其他豇豆属物种，这表明质膜中存在更多的多不饱和脂肪酸，这可能导致叶绿体等膜结合细胞器严重受损，以及在热应激期间电解质泄漏增加。这项研究为鉴定候选基因铺平了道路，这些基因可用于培育耐热的兵豆品种。
