Objective Cassava is an important food and economic crop in tropical regions worldwide, and it is highly susceptible to yield reduction due to non-biological stresses such as low temperature, drought, and salinity during its growth and development. Stress-associated proteins (SAPs) are a novel class of A20/AN1 zinc finger proteins that play important roles in the response of model crops to various non-biological stresses. The biological functions of SAPs in cassava’s response to non-biological stresses are not yet clear. This study aims to analyze the protein structure characteristics and expression patterns of the cassava SAPs, as well as the interacting proteins of MeSAP11, and provide theoretical support for further understanding the function of cassava SAPs in response to abiotic stresses.
Method Bioinformatics techniques were used to systematically analyze the evolutionary relationships, protein motif information, and spatiotemporal expression patterns of the cassava SAPs. Additionally, qRT-PCR was used to study the specific expression of each gene member in different tissues and their response to abiotic stresses. Furthermore, yeast two-hybrid combined with high-throughput sequencing technology was used to identify the proteins interacting with MeSAP11 and their corresponding biological pathways.
Result The cassava SAP gene family consisted of six major classes and 16 members. The expression levels of these family members were higher in cassava roots and leaves. The expressions of several family members were significantly up-regulated by low temperature and salt stress, and significantly down-regulated by drought, potassium starvation and nitrogen starvation. The expression of MeSAP11 was significantly regulated under different stress conditions, and subcellular localization results indicated that the MeSAP11 protein was mainly located in the nucleus. Using yeast two-hybrid screening, 256 proteins were identified to interact with MeSAP11, and KEGG analysis indicated that these interacting genes are mainly involved in protein ubiquitination degradation and endoplasmic reticulum protein processing pathways, suggesting that MeSAP11 may function through these pathways.
Conclusion The majority of the cassava SAPs are significantly regulated by low temperature, drought, high salinity, nitrogen deficiency, and potassium deficiency stresses. These results lay a theoretical fundation for the function exploration of MeSAP11 in cassava responding to abiotic stress, and point out a direction for further study to unravel its regulatory network. MeSAP11 is identified as a candidate gene for further in-depth research on regulating non-biological stress changes.
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