Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 ...Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.展开更多
Walnut anthracnose induced by Colletotrichum gloeosporioides is a disastrous disease that severely restricts the development of the walnut industry in China.Long non-coding RNAs(lncRNAs)are involved in adaptive respon...Walnut anthracnose induced by Colletotrichum gloeosporioides is a disastrous disease that severely restricts the development of the walnut industry in China.Long non-coding RNAs(lncRNAs)are involved in adaptive responses to disease,but their roles in the regulation of walnut anthracnose resistance response are not well defined.In this study,transcriptome analysis demonstrated that a C.gloeosporioides-induced lncRNA,lncRNA109897,located upstream from the target gene JrCCR4,upregulated the expression of JrCCR4.JrCCR4 interacted with JrTLP1b and promoted its transcriptional activity.In turn,JrTLP1b induced the transcription of lncRNA109897 to promote its expression.Meanwhile,transient expression in walnut leaves and stable transformation of Arabidopsis thaliana further proved that lncRNA,JrCCR4,and JrTLP1b improve the resistance of C.gloeosporioides.Collectively,these findings provide insights into the mechanism by which the lncRNA109897-JrCCR4-JrTLP1b transcriptional cascade regulates the resistance of walnut to anthracnose.展开更多
文摘Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.
基金This work is supported by the National Natural Science Foundation of China(32001340)the Improved Variety Program of Shandong Province of China(2020LZGC090102)the Natural Science Foundation of Shandong Province(ZR2020QC169)。
文摘Walnut anthracnose induced by Colletotrichum gloeosporioides is a disastrous disease that severely restricts the development of the walnut industry in China.Long non-coding RNAs(lncRNAs)are involved in adaptive responses to disease,but their roles in the regulation of walnut anthracnose resistance response are not well defined.In this study,transcriptome analysis demonstrated that a C.gloeosporioides-induced lncRNA,lncRNA109897,located upstream from the target gene JrCCR4,upregulated the expression of JrCCR4.JrCCR4 interacted with JrTLP1b and promoted its transcriptional activity.In turn,JrTLP1b induced the transcription of lncRNA109897 to promote its expression.Meanwhile,transient expression in walnut leaves and stable transformation of Arabidopsis thaliana further proved that lncRNA,JrCCR4,and JrTLP1b improve the resistance of C.gloeosporioides.Collectively,these findings provide insights into the mechanism by which the lncRNA109897-JrCCR4-JrTLP1b transcriptional cascade regulates the resistance of walnut to anthracnose.
