Intertwined signatures of desiccation and drought tolerance in grasses
Intertwined signatures of desiccation and drought tolerance in grasses
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DOI：
10.1073/pnas.2001928117
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发表时间：
2020-05-05
影响因子：
11.1
通讯作者：
VanBuren, Robert
中科院分区：
文献类型：
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作者：
Pardo, Jeremy;Wai, Ching Man;VanBuren, Robert
草类植物是最具弹性的植物之一，有些植物可以在半干旱地区的季节性降雨中存活下来。然而，区分草对极端干燥敏感和耐受的遗传因素在很大程度上是未知的。在这里，我们利用比较基因组方法与耐干燥的草Eragrostis nindensis和相关的干燥敏感的谷物Eragrostis tef来确定干旱耐受性的变化。这些分析扩展到C4草和谷物，以确定更广泛的进化保护和分化。通过不同的基因组数据集，我们确定了与E. nindensis干燥相关的染色质结构、甲基化、基因复制和表达动态的变化。以前的假设是，种子干燥途径的转录重组赋予了营养的干燥耐受性。在这里，我们证明了大多数种子脱水相关基因在干燥耐受性和敏感物种的叶片中表现出相似的表达模式。然而，我们发现了一小部分与种子相关的同源基因，这些基因的表达是耐干燥物种特有的。这支持了种子相关基因的广泛作用，其中许多基因参与了典型的干旱反应，只有一小部分关键基因在耐干旱植物中被特异性诱导。
Grasses are among the most resilient plants, and some can survive prolonged desiccation in semiarid regions with seasonal rainfall. However, the genetic elements that distinguish grasses that are sensitive versus tolerant to extreme drying are largely unknown. Here, we leveraged comparative genomic approaches with the desiccation-tolerant grass Eragrostis nindensis and the related desiccation-sensitive cereal Eragrostis tef to identify changes underlying desiccation tolerance. These analyses were extended across C4 grasses and cereals to identify broader evolutionary conservation and divergence. Across diverse genomic datasets, we identified changes in chromatin architecture, methylation, gene duplications, and expression dynamics related to desiccation in E. nindensis. It was previously hypothesized that transcriptional rewiring of seed desiccation pathways confers vegetative desiccation tolerance. Here, we demonstrate that the majority of seed-dehydration-related genes showed similar expression patterns in leaves of both desiccation-tolerant and -sensitive species. However, we identified a small set of seed-related orthologs with expression specific to desiccation-tolerant species. This supports a broad role for seed-related genes, where many are involved in typical drought responses, with only a small subset of crucial genes specifically induced in desiccation-tolerant plants.