Genomic Identification of CCCH-Type Zinc Finger Protein Genes Reveals the Role of HuTZF3 in Tolerance of Heat and Salt Stress of Pitaya (Hylocereus polyrhizus)

Pitaya (Hylocereus polyrhizus) is cultivated in a broad ecological range, due to its tolerance to drought, heat, and poor soil. The zinc finger proteins regulate gene expression at the transcriptional and post-transcriptional levels, by interacting with DNA, RNA, and proteins, to play roles in plant growth and development, and stress response. Here, a total of 81 CCCH-type zinc finger protein genes were identified from the pitaya genome. Transcriptomic analysis showed that nine of them, including HuTZF3, responded to both salt and heat stress. RT-qPCR results showed that HuTZF3 is expressed in all tested organs of pitaya, with a high level in the roots and stems, and confirmed that expression of HuTZF3 is induced by salt and heat stress. Subcellular localization showed that HuTZF3 is targeted in the processing bodies (PBs) and stress granules (SGs). Heterologous expression of HuTZF3 could improve both salt and heat tolerance in Arabidopsis, reduce oxidative stress, and improve the activity of catalase and peroxidase. Therefore, HuTZF3 may be involved in post-transcriptional regulation via localizing to PBs and SGs, contributing to both salt and heat tolerance in pitaya.

Automated summary

Pitaya, a plant with tolerance to drought, heat, and poor soil, has gene expression and stress response regulated by zinc finger proteins. A total of 81 CCCH-type zinc finger protein genes were identified in the pitaya genome, and HuTZF3 was found to respond to both salt and heat stress. HuTZF3 showed expression in all tested organs of pitaya, especially with high levels in roots and stems, and its expression was induced by salt and heat stress. Subcellular localization revealed that HuTZF3 is targeted in processing bodies and stress granules. Heterologous expression of HuTZF3 in Arabidopsis improved salt and heat tolerance, reduced oxidative stress, and enhanced the activity of catalase and peroxidase. Thus, HuTZF3 may contribute to post-transcriptional regulation via its localization in processing bodies and stress granules, contributing to salt and heat tolerance in pitaya.