Integrated analysis of high-throughput sequencing data shows abscisic acidresponsive genes and miRNAs in strawberry receptacle fruit ripening

The perception and signal transduction of the plant hormone abscisic acid(ABA)are crucial for strawberry fruit ripening,but the underlying mechanism of how ABA regulates ripening-related genes has not been well understood.By employing high-throughput sequencing technology,we comprehensively analyzed transcriptomic and miRNA expression profiles simultaneously in ABA-and nordihydroguaiaretic acid(NDGA,an ABA biosynthesis blocker)-treated strawberry fruits with temporal resolution.The results revealed that ABA regulated many genes in different pathways,including hormone signal transduction and the biosynthesis of secondary metabolites.Transcription factor genes belonging to WRKY and heat shock factor(HSF)families might play key roles in regulating the expression of ABA inducible genes,whereas the KNOTTED1-like homeobox protein and Squamosa Promoter-Binding-like protein 18 might be responsible for ABA-downregulated genes.Additionally,20 known and six novel differentially expressed miRNAs might be important regulators that assist ABA in regulating target genes that are involved in versatile physiological processes,such as hormone balance regulation,pigments formation and cell wall degradation.Furthermore,degradome analysis showed that one novel miRNA,Fa_novel6,could degrade its target gene HERCULES1,which likely contributed to fruit size determination during strawberry ripening.These results expanded our understanding of how ABA drives the strawberry fruit ripening process as well as the role of miRNAs in this process.

MYB41,MYB107,and MYC2 promote ABA-mediated primary fatty alcohol accumulation via activation of AchnFAR in wound suberization in kiwifruit

Wound damage triggers the accumulation of abscisic acid(ABA),which induces the expression of a large number of genes involved in wound suberization in plants.Fatty acyl-CoA reductase(FAR)catalyzes the generation of primary fatty alcohols by the reduction of fatty acids in suberin biosynthesis.However,the regulatory effects of transcription factors(TFs)on AchnFAR in response to ABA are unexplored.In this study,kiwifruit AchnFAR displayed a biological function analogous to that of FAR in transiently overexpressed tobacco(Nicotiana benthamiana)leaves.The positive role of TFs,including AchnMYB41,AchnMYB107,and AchnMYC2,in the regulation of AchnFAR was identified.The three TFs could individually bind to the AchnFAR promoter to activate gene transcription in yeast one-hybrid and dualluciferase assays.Transient overexpression of TFs in tobacco leaves resulted in the upregulation of aliphatic synthesis genes(including FAR)and the increase in aliphatics,including primary alcohols,α,ω-diacids,ω-hydroxyacids,and fatty acids.Moreover,exogenous ABA treatment elevated TF-mediated AchnFAR expression and the accumulation of primary alcohols.Conversely,fluridone,an inhibitor of ABA biosynthesis,suppressed the expression of AchnFAR and TF genes and reduced the formation of primary alcohols.The results indicate that AchnMYB41,AchnMYB107,and AchnMYC2 activate AchnFAR transcription to promote ABA-mediated primary alcohol formation in wound suberization in kiwifruit.