MicroRNAs as master regulators of the plant NB-LRR defense gene family via the production of phased, trans-acting siRNAs
MicroRNAs as master regulators of the plant NB-LRR defense gene family via the production of phased, trans-acting siRNAs
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DOI：
10.1101/gad.177527.111
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发表时间：
2011-12-01
影响因子：
10.5
通讯作者：
Meyers, Blake C.
中科院分区：
文献类型：
--
作者：
Zhai, Jixian;Jeong, Dong-Hoon;Meyers, Blake C.
豆科植物和许多非豆科植物与微生物进入共生相互作用，而寄主植物如何促进有益的共生微生物相互作用，同时抑制那些有害或致病的微生物相互作用，目前尚不清楚。反式作用sirna （tasirna）负调控靶转录物，其特征是sirna以21个核苷酸（nt）“阶段性”间隔间隔，这是DICER-LIKE 4 （DCL4）加工形成的模式。对阶段性sirna （phasiRNAs）的搜索发现了至少114个紫花苜蓿位点，其中大多数是与防御相关的nb - lrr编码基因。我们确定了三个高度丰富的22-nt microRNA （miRNA）家族，它们靶向这些nb - lrr中的保守结构域并触发反式sirna的产生。高水平的小rna与所有与540个编码的Medicago nb - lrr相似的rna相匹配；在马铃薯中，作为菌根相互作用的模型，也从nb - lrs中产生了相rna。DCL2和SGS3转录本也被这些22-nt mirna切割，产生phasirna，表明沉默和病原体防御途径之间存在同步。此外，还发现了一个明显的“双击”phasiRNA加工的新例子。我们的数据揭示了基于tasirna的nb - lrs的复杂调控，这些调控可能进化为促进共生相互作用，并通过靶向高度保守的蛋白质编码基序（miRNA功能的新范式）证明miRNA是一个大基因家族的主要调节剂。
Legumes and many nonleguminous plants enter symbiotic interactions with microbes, and it is poorly understood how host plants respond to promote beneficial, symbiotic microbial interactions while suppressing those that are deleterious or pathogenic. Trans-acting siRNAs (tasiRNAs) negatively regulate target transcripts and are characterized by siRNAs spaced in 21-nucleotide (nt) "phased'' intervals, a pattern formed by DICER-LIKE 4 (DCL4) processing. A search for phased siRNAs (phasiRNAs) found at least 114 Medicago loci, the majority of which were defense-related NB-LRR-encoding genes. We identified three highly abundant 22-nt microRNA (miRNA) families that target conserved domains in these NB-LRRs and trigger the production of trans-acting siRNAs. High levels of small RNAs were matched to >60% of all similar to 540 encoded Medicago NB-LRRs; in the potato, a model for mycorrhizal interactions, phasiRNAs were also produced from NB-LRRs. DCL2 and SGS3 transcripts were also cleaved by these 22-nt miRNAs, generating phasiRNAs, suggesting synchronization between silencing and pathogen defense pathways. In addition, a new example of apparent "two-hit'' phasiRNA processing was identified. Our data reveal complex tasiRNA-based regulation of NB-LRRs that potentially evolved to facilitate symbiotic interactions and demonstrate miRNAs as master regulators of a large gene family via the targeting of highly conserved, protein-coding motifs, a new paradigm for miRNA function.