Cloning and expression analysis of a MAP3K gene in banana北大核心CSCD

To investigate the sequence characteristics of a low-temperature inducible banana MAP3K gene and to explore the expression patterns of the gene together with the miRNA (miR408d) and lncRNA (MSTRG.4851) targeting it, the MAP3K gene was cloned from ‘Tianbaojiao’ banana using reverse transcription PCR (RT-PCR). The sequence characteristics of the gene and its encoded proteins were analyzed bioinformatically. Based on long noncoding RNA (lncRNA) and small RNA (sRNA) sequencing data, the expression patterns of MAP3KmiRNA408d-lncRNA were studied and confirmed using quantitative real-time PCR (qRT-PCR). The results showed that the coding sequence (CDS) of MAP3K was 2 262 bp, which encoded an unstable hydrophilic protein with the molecular formula C3566H5625N1047O1090S32, amino acid size of 753 aa, molecular weight of 81 631.17, and isoelectric point of 9.33. MAP3K was of conserved PKinase and MEKK domain that lacks a transmembrane structure and a signal peptide. The relationship between MAP3K and Musa acuminata MAP3K was the closest. The subcellular localization prediction results showed that MAP3K was mainly localized in the outer membrane. Protein-protein interaction prediction results showed that MAP3K could interact with three MAP2K proteins belonging to subfamily A of the MAPKK gene family. The MAP3K promoter contained many light- and hormone-responsive elements. qRT-PCR results showed that the expression of MAP3K was low temperature-inducible, but the expression of the miRNA and lncRNA targeting it was significantly induced by low temperature, which was consistent with the lncRNA and sRNA sequencing data. The results obtained in this study indicated that the expression of MAP3K is regulated by miRNAs and lncRNAs and might contribute greatly to the low-temperature stress response of banana. © 2022 Science Press. All rights reserved.