The Sugar Transporter Gene Family in Colored Calla Lily: Identification, Expression Patterns, and Roles in Soft Rot...

Carbohydrates are a primary nutrient for plant growth, and sugar transporter proteins play a crucial role in sugar allocation. In this study, hexose transporter genes encoding in the genome of colored calla lily 'Jingcai Yangguang' (Zantedeschia elliottiana cv. Jingcai Yangguang) were identified, and their expression patterns following infection by Pectobacterium carotovora subsp. Carotovora were investigated. Additionally, the transport characteristics of three hexose transporters, ZeSTP7, ZeSTP15, and ZeSTP17, were determined. The results showed that the sugar transporter protein family in Z. elliottiana comprises 18 members, most of which possess 12 transmembrane domains. Phylogenetic analysis revealed that the ZeSTP gene family was divided into five subgroups. Tandem gene duplication events were identified on the 16 chromosomes of Z. elliottiana, with multiple tandemly duplicated genes detected. Comparative analysis of synteny between species identified ZeSTP8 and OsSTP22 as homologous gene pairs, while OsSTP6 (OsMST6) was identified as a homologous gene pair with both ZeSTP14 and ZeSTP17. Following infection by P. carotovora subsp. carotovora, the transcript levels of ZeSTP7, ZeSTP15, and ZeST17 were all significantly elevated. Yeast mutant hexose complementation tests indicated that ZeSTP7 could transport glucose and galactose, whereas ZeSTP15 and ZeSTP17 exhibited limited transport capacity in this respect. This study provides a systematic identification and analysis of hexose transporter genes at the genome-wide level, highlighting the role of ZeSTP genes in the response of colored calla lily to soft rot and laying a theoretical foundation for further understanding the functions of sugar transporter genes.