Calmodulin-like proteins (CMLs) have been shown to play key regulatory roles in calcium signaling in plants. However, few bona-fide CMLs binding proteins have been characterized in rice, a monocot model plant. Here, through large-scale screening of a yeast-two hybrid (Y2H) cDNA library with OsCML16 as a bait, six new putative interacting partners of OsCML16 were discovered and confirmed by both pairwise Y2H and bimolecular fluorescence complementation (BiFC) assays. Interestingly, the in vitro peptide-binding assays manifested that OsERD2 could bind both OsCaM1 and OsCML16 whereas other five target proteins could specifically bind OsCML16 but not OsCaM1. Furthermore, Ca2+ and TFP, a calmodulin (CaM) antagonist, were involved in the ABA-induced transcription of OsCML16 and its target genes, and they were also obviously induced by cold, drought, and salt stresses. Taken together, our new findings have provided the basis for the novel signaling pathways of OsCML16 in the abiotic stress response in rice.

中文翻译：

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水稻非生物胁迫下新型OsCML16靶蛋白的鉴定及差异表达分析

钙调蛋白样蛋白 (CML) 已被证明在植物钙信号传导中发挥关键调节作用。然而，很少有真正的 CML 结合蛋白在单子叶植物模式植物水稻中得到表征。在这里，通过以 OsCML16 为诱饵对酵母-双杂交 (Y2H) cDNA 文库进行大规模筛选，发现并通过成对 Y2H 和双分子荧光互补 (BiFC) 分析证实了 OsCML16 的六个新的假定相互作用伙伴。有趣的是，体外肽结合试验表明 OsERD2 可以结合 OsCaM1 和 OsCML16，而其他五种靶蛋白可以特异性结合 OsCML16 但不能结合 OsCaM1。此外，钙调蛋白（CaM）拮抗剂 Ca2+和 TFP 参与了 ABA 诱导的 OsCML16 及其靶基因的转录，它们也明显受到寒冷、干旱、和盐胁迫。总之，我们的新发现为 OsCML16 在水稻非生物胁迫响应中的新信号通路提供了基础。