Transcriptome analyses and virus‐induced gene silencing identify HuWRKY40 acting as a hub transcription factor in the preservation of Hylocereus undatus by trypsin

Abstract

Trypsin can significantly improve the storage quality of Hylocereus undatus (H. undatus). To verify the hub WRKY gene of H. undatus in trypsin preservation, joint analysis of transcriptome and protein–protein interaction (PPI) network was carried out, and virus‐induced gene silencing (VIGS) was conducted. In the transcriptome of H. undatus, GO directed acyclic graph (DAG) showed that the GO terms of 55 WRKY genes were mainly enriched in sequence‐specific DNA binding, DNA binding transcription factor activity, and so on. The GO enrichment chord diagram showed that HuWRKY40 was significantly up‐regulated in the enriched top10 GO terms. KEGG enrichment analysis showed that 55 WRKY genes were mainly enriched in plant–pathogen interaction and MAPK pathway. The results of PPI network showed that HuWRKY40 was a hub protein of WRKY transcription factors (TFs) family regulated by trypsin, which was consistent with the results of transcriptome analysis. Bioinformatics analysis showed that HuWRKY40 of H. undatus had the highest homology with Beta vulgaris L. and Spinacia oleracea L. The function of the core regulatory protein HuWRKY40 was further clarified by VIGS technology. The results of VIGS showed that there was a big difference between the phenotype of the pTRV2‐HuWRKY40 group and that of the control group. Finally, it was confirmed that HuWRKY40 accelerated the synthesis of flavonoids and improved the fruit quality during the storage of H. undatus. This study found that trypsin may regulate HuWRKY40 activity through the MAPK cascade pathway, affect the participation of flavonoid synthesis, and then delay fruit corruption. Practical applications With attention of people to the safety and freshness of fruits and vegetables, biological preservation technology has become one of the hotspots in the field of preservation in recent years. Trypsin can significantly improve the antioxidant capacity of fruits and vegetables. As a new biological preservative, it is convenient to operate and economical. In the current work, the mechanism of trypsin on the WRKY TFs during H. undatus storage was investigated. The application of trypsin would provide a new strategy for the storage quality control of fruits and vegetables.

PTI‐ETI synergistic signal mechanisms in plant immunity

“…MYB, ERF, NAC, MYC and WRKY family members function by regulating defence responses following MAPK cascade phosphorylation (Amorim et al ., 2017; Welch et al ., 2022; Zhao et al ., 2021a). WRKY70, WRKY33, WRKY22, WRKY29, WRKY40 and WRKY104 participate in plant defence responses through transcriptional and post‐transcriptional regulation of the MAPK cascade (Asai et al ., 2002; Hsu et al ., 2013; Wang et al ., 2022a; Zhang et al ., 2022; Zhao et al ., 2021b; Zhou et al ., 2022). Phosphorylation of ZmNAC49 by ZmMAPK5 enhances its binding activity to the ZmSOD3 promoter, improving plant oxidative stress tolerance (Xiang et al ., 2021).…”

CsWRKY33: A Crucial Transcription Factor in the MAPK Pathway Inhibited by Trypsin, Participating in the Suppression of Cucumis sativus Senescence

“…The sequencing protocol employed the Illumina TruSeqTM RNA Sample Prep Kit for the construction of sequencing libraries. Total RNA was extracted, and the RNA Integrity Number (RIN) was quanti ed using the Agilent 2100 system [30]. Subsequently, the Illumina HiSeq platform was utilized for on-machine sequencing using paired-end sequencing (PE library) with a read length of 2x150 bp.…”

“…Subsequently, a phylogenetic tree was generated through the application of the Neighbor-Joining method using the MEGA6.0 software package. Furthermore, the theoretical isoelectric point and relative molecular weight of CsWRKY33were predicted via the web resource http://web.expasy.org/Compute_pi/ [30].…”

“…Due to its ability to scavenge superoxide anions, trypsin could modulate endogenous reactive oxygen species (ROS) levels in dragon fruit peels and inhibit saturated fatty acid levels. It also induced the biosynthesis of compounds involved in the phenylpropanoid pathway, such as lignin, chlorogenic acid [21,22], and avonoids [23,24]. Furthermore, it could in uence the activity of avonoids in scavenging free radicals, such as DPPH and ABTS [25,26], thereby enhancing fruit resistance.…”