Objective This study aims to discover members of the Al-activated malate transporter ALMT gene family that may be involved in the growth and development of litchi and to investigate their biological functions.

Method The physicochemical properties of proteins, subcellular localisation predictions, phylogeny, gene structure, conservative motifs, chromosomal positioning, promoter cis-acting elements, protein structure and expression patterns of litchi ALMT gene family members were systematically analysed using bioinformatics methods, expression of the litchi LcALMTs was analysed by qPCR.

Result The results showed that the litchi LcALMT gene family has 16 members with CDS lengths ranging from 118 to 803 bp and isoelectric points between 5.16 and 9.07. Subcellular localisation predictions showed that the LcALMTs were all localised to the plasma membrane, and the family was divided into five subclades based on a phylogenetic tree. The number of exons of the LcALMTs ranged from 3 to 10, and four LcALMT genes did not contain any non-coding regions. Chromosomal localisation analysis revealed that LcALMTs was localised on only six of the 15 chromosomes of litchi, and mainly on chromosome 13. Conservative motif analysis revealed that litchi ALMT family members contain both ALMT and ALMT superfamily structural domains. Among the cis-acting elements, light-responsive elements accounted for the largest proportion, followed by hormone-responsive elements. Expression pattern analysis revealed that the expression of Litchi LcALMTs was highly variable in different tissues, with LcALMT5 and LcALMT15 being expressed at high levels in all tissues, the qPCR results showed that the expression level of LcALMT5 was more consistent with the results of the transcriptome.

Conclusion There are 16 members of the litchi ALMT Gene family, which has a conservative gene structure and protein domain, and there are differences in tissue expression.