Evolution of PHAS loci in the young spike of Allohexaploid wheat
Evolution of PHAS loci in the young spike of Allohexaploid wheat
复制标题
异源六倍体小麦幼穗PHAS位点的进化
DOI：
10.1186/s12864-020-6582-4
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发表时间：
2020
期刊：
影响因子：
4.4
通讯作者：
Genying Li
中科院分区：
文献类型：
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作者：
Rongzhi Zhang;Siyuan Huang;Shiming Li;Guoqi Song;Yulian Li;Wei Li;Jihu Li;Jie Gao;Tiantian Gu;D;an Li;Shujuan Zhang;Genying Li
背景PhasiRNA（分相次级siRNA）在植物的发育过程和生物或非生物胁迫中发挥着重要的调节作用。一些phasiRNA参与草类的生殖发育，包括两类：21-nt（核苷酸）和24-nt phasiRNA。它们分别由水稻、玉米和其他禾本科植物减数分裂前和减数分裂花药中的 miR2118 和 miR2275 触发。小麦（Triticum aestivum）具有三个密切相关的亚基因组（subA、subB 和 subD），是植物异源多倍体的模型。目前对phasiRNA在小麦花序发育中的作用尚不了解，多倍体植物中PHAS位点的进化也尚不清楚。结果利用来自不同组织的261个小RNA表达数据集，在小麦幼穗中鉴定了一批PHAS（phasiRNA前体）位点，其中大部分在其靶位点区域受到miR2118和miR2275的调控。对小麦二倍体(AA和DD)、四倍体(AABB)和六倍体(AABBDD)基因组中PHAS及其触发miRNA的解剖表明，PHAS位点在局部染色体中随机占主导地位，而miR2118仅在subB基因组中占主导地位。小麦三个亚基因组及其祖先基因组（AA、DD和AABB）中PHAS位点的多样性表明它们至少在四倍体AABB基因组出现之前起源或分化。小麦PHAS位点或触发miRNA与基因组倍性呈正相关，表明基因组扩张是小麦PHAS位点及其触发miRNA增加的主要驱动力。此外，PHAS转录本的表达谱表明它们对非生物胁迫（例如小麦的冷胁迫）有反应。结论总而言之，非编码phasiRNA是保守的转录调节因子，在小麦基因组中表现出快速可塑性。它们可能参与小麦的生殖发育和非生物胁迫。可以参考小麦雄性生殖发育的分子研究。
BackgroundPhasiRNAs (phased secondary siRNAs) play important regulatory roles in the development processes and biotic or abiotic stresses in plants. Some of phasiRNAs involve in the reproductive development in grasses, which include two categories, 21-nt (nucleotide) and 24-nt phasiRNAs. They are triggered by miR2118 and miR2275 respectively, in premeiotic and meiotic anthers of rice, maize and other grass species. Wheat (Triticum aestivum) with three closely related subgenomes (subA, subB and subD), is a model of allopolyploid in plants. Knowledge about the role of phasiRNAs in the inflorescence development of wheat is absent until now, and the evolution ofPHASloci in polyploid plants is also unavailable.ResultsUsing 261 small RNA expression datasets from various tissues, a batch ofPHAS(phasiRNA precursors) loci were identified in the young spike of wheat, most of which were regulated by miR2118 and miR2275 in their target site regions. Dissection ofPHASand their trigger miRNAs among the diploid (AA and DD), tetraploid (AABB) and hexaploid (AABBDD) genomes ofTriticumindicated that distribution ofPHASloci were dominant randomly in local chromosomes, while miR2118 was dominant only in the subB genome. The diversity ofPHASloci in the three subgenomes of wheat and their progenitor genomes (AA, DD and AABB) suggested that they originated or diverged at least before the occurrence of the tetraploid AABB genome. The positive correlation between thePHASloci or the trigger miRNAs and the ploidy of genome indicated the expansion of genome was the major drive force for the increase ofPHASloci and their trigger miRNAs inTriticum. In addition, the expression profiles of thePHAStranscripts suggested they responded to abiotic stresses such as cold stress in wheat.ConclusionsAltogether, non-coding phasiRNAs are conserved transcriptional regulators that display quick plasticity inTriticumgenome. They may be involved in reproductive development and abiotic stress in wheat. It could be referred to molecular research on male reproductive development inTriticum.