Identification and characterization of HVA22 genes in pineapple (Ananas comosus L.) revealed their potential roles in development regulation and cold stress response.

backgroundPineapple (Ananas comosus L.), an economically significant tropical fruit crop, is highly susceptible to low-temperature during cultivation. The abscisic acid (ABA) and stress-inducible HVA22 gene family is known to play important roles in growth regulation and abiotic stress response, but its functions in pineapple remain unclear.

resultsWe identified 11 HVA22 genes (AcHVA22A - AcHVA22K) in the pineapple genome and grouped them into four phylogenetic clades. Expression analysis showed that most AcHVA22 genes displayed tissue- or developmental stage-specific expression patterns, suggesting their diverse functions in pineapple growth and development. Subcellular localization analyses revealed diverse localizations of AcHVA22 proteins, including plasma membrane, cytoplasm, and nucleus. And regulatory predictions indicated control by multiple cis-elements, transcription factors, and miRNAs, which may contribute to their functional diversification. Most AcHVA22 genes responded consistently to ABA, GA, and drought treatments, but their responses to high and low-temperatures varied. Notably, AcHVA22C/D/E/G/I/K were up-regulated under both short- and long-term cold treatments in two different pineapple varieties, highlighting their potential key roles in cold stress tolerance.

conclusionsThis study provided the first genome-wide characterization of the HVA22 gene family in pineapple. The identification of candidate genes involved in cold stress response offers new insights into HVA22 functions in tropical fruits and provides valuable resources for improving cold resistance in pineapple breeding.