https://mp.weixin.qq.com/s/IN7f6Qent8ZWtqLFOvMMJw

近日，由河北農(nóng)大王立新-劉志國團(tuán)隊(duì)在PCE發(fā)表了題為《ZjMAPKK4 Interacted With ZjNAC78 Regulates Cold Tolerance Response in Jujube》的研究論文，揭示了棗樹中ZjMAPKK4與ZjNAC78互作調(diào)節(jié)耐寒響應(yīng)。

在中國，棗樹（Ziziphus jujuba Mill）是一種重要的果樹作物，它具有較強(qiáng)的耐旱性和耐鹽性，但其對(duì)冷脅迫較為敏感。MAPK級(jí)聯(lián)是一種重要的信號(hào)通路，但其在介導(dǎo)棗樹冷脅迫反應(yīng)中的作用尚不清楚，ZjMAPKK4在這一背景下的具體功能也尚未完全闡明。

因此，在本研究中，作者發(fā)現(xiàn)與其它ZjMAPK級(jí)聯(lián)基因相比，冷處理后ZjMAPKK4顯著上調(diào)。在擬南芥中異源轉(zhuǎn)化ZjMAPKK4，VIGS誘導(dǎo)的ZjMAPKK4瞬時(shí)沉默以及棗愈傷組織中ZjMAPKK4的過表達(dá)實(shí)驗(yàn)表明，ZjMAPKK4正向調(diào)控棗樹的抗寒性。

此外，為了闡明ZjMAPKK4在冷脅迫下背后的分子調(diào)控機(jī)制，通過轉(zhuǎn)錄組分析篩選出25個(gè)關(guān)鍵差異表達(dá)基因（DEGs）。酵母篩選cDNA庫、酵母雙雜交、LCA和Co-IP分析顯示，ZjMAPKK4與ZjNAC78相互作用，且VIGS誘導(dǎo)的ZjNAC78沉默后，棗樹表現(xiàn)出對(duì)冷的敏感性，冷脅迫后冷響應(yīng)基因的表達(dá)水平也隨之下調(diào)。

以上結(jié)果表明，ZjMAPKK4可以與ZjNAC78相互作用，調(diào)節(jié)下游的ZjICE-ZjCBF基因來介導(dǎo)棗樹的抗寒性。

Jujube (Ziziphus jujuba Mill.) holds great importance as a fruit tree in China, with strong tolerance to drought and saline stress, but its growth is limited by vulnerability to cold stress. Consequently, the role of MAPK cascades in mediating jujube cold stress response remains unclear, with the specific function of ZjMAPKK4 in this context yet to be fully elucidated. Thus, in the current study, it was found that ZjMAPKK4 was significantly upregulated compared with other ZjMAPK cascade genes after cold treatment. Heterologous transformation of ZjMAPKK4 in Arabidopsis, VIGS-induced ZjMAPKK4 transiently silencing and overexpression of ZjMAPKK4 in jujube callus assays demonstrated that ZjMAPKK4 positively regulated the cold resistance of jujube. Furthermore, to elucidate the molecular regulation mechanism behind ZjMAPKK4 under cold stress, 25 key DEGs were screened out by transcriptome analysis. Yeast screening cDNA library, yeast two-hybrid, LCA and Co-IP analysis showed ZjMAPKK4 interacted with ZjNAC78 and VIGS-induced ZjNAC78 silenced sour jujube plants showed cold sensitivity and the expression level of cold response genes were downregulated after cold stress. All the results demonstrated that ZjMAPKK4 could interact with ZjNAC78 to regulate the downstream ZjICE-ZjCBF genes to regulate the cold tolerance of jujube.

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