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

Pitaya () 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 , responded to both salt and heat stress. RT-qPCR results showed that is expressed in all tested organs of pitaya, with a high level in the roots and stems, and confirmed that expression of 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 could improve both salt and heat tolerance in , 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.