Genome-Wide Identification and Characterization of DnaJ Gene Family in Grape (Vitis vinifera L.)

Grape production in southern China suffers great loss due to various environmental stresses. To understand the mechanism of how the grape plants respond to these stresses is an active area of research in developing cultivation techniques. Plant stress resistance is known to rely on special proteins. Amongst them, DnaJ protein (HSP40) serves as co-chaperones of HSP70, playing crucial roles in various stress response. However, the DnaJ proteins encoded by the DnaJ gene family in Vitis vinifera L. have not been fully described yet. In this study, we identified 78 VvDnaJs in the grape genome that can be classified into three groups—namely, DJA, DJB, and DJC. To reveal the evolutionary and stress response mechanisms for the VvDnaJ gene family, their evolutionary and expression patterns were analyzed using the bioinformatic approach and qRT-PCR. We found that the members in the same group exhibited a similar gene structure and protein domain organization. Gene duplication analysis demonstrated that segmental and tandem duplication may not be the dominant pathway of gene expansion in the VvDnaJ gene family. Codon usage pattern analysis showed that the codon usage pattern of VvDnaJs differs obviously from the monocotyledon counterparts. Tissue-specific analysis revealed that 12 VvDnaJs present a distinct expression profile, implying their distinct roles in various tissues. Cis-acting element analysis showed that almost all VvDnaJs contained the elements responsive to either hormones or stresses. Therefore, the expression levels of VvDnaJs subjected to exogenous hormone applications and stress treatments were determined, and we found that VvDnaJs were sensitive to hormone treatments and shade, salt, and heat stresses, especially VIT_00s0324g00040. The findings of this study could provide comprehensive information for the further investigation on the genetics and protein functions of the DnaJ gene family in grape.

Identification Method of Drought Resistance on Maize Based on qRT-PCR

Background: In order to reveal the mechanism of drought resistance of maize, establish the molecular identification system of drought resistance and solve the problem of difficult identification of drought resistance of maize. Taking Nongdan 476, a drought-tolerant maize hybrid cultivar, and Zhongxin 978, a drought-sensitive maize hybrid cultivar, as materials, drought stress and normal watering treatment were carried out at seedling stage, flare stage, tasseling stage and filling stage, and leaf tissue were collected for transcriptomes.Results: P-vaule < 0.05 was selected as the screening standard. There were 6281, 17191, 21790 and 15475 differentially expressed genes of each stage, respectively. At the same time, only DnaJ gene was significantly differentially expressed at the four stages. The preliminary results of qRT-PCR showed that the up regulation of DnaJ gene expression was consistent with the results of transcriptome analysis. DnaJ gene expression was further detected by using control samples with specific drought resistance index of yield. The results showed that DnaJ gene expression drought resistance index (DIE) was highly correlated with yield drought resistance index (DIP), and the 5-level criteria for DnaJ gene expression drought resistance index (DIE) were defined by their linear equations. Conclusion: Drought resistance of maize is a character controlled by multiple genes. There is a significant difference between the expression of DnaJ gene in drought resistant and non drought resistant maize, which has the potential to be used as molecular identification of drought resistance of maize, and can provide a more comprehensive and accurate technical means for drought resistance cultivation and breeding of maize.