Identification of the AkLOX gene family in Amorphophallus konjac and analysis of its expression patterns under different treatments

BACKGROUND: The Amorphophallus konjac is an important specialty cash crop in China and is rich in konjac glucomannan (KGM); however, its long-term exposure to abiotic and biotic stresses has hindered the development of the industry. Lipoxygenase (LOX) is a key enzyme in plant fatty acid metabolism and stress response, playing a vital role in plant growth and development, regulation of secondary metabolism, and responses to biotic and abiotic stresses. To date, systematic studies on the LOX gene family in A. konjac remain lacking. This study aims to identify the A. konjac LOX gene family at the whole-genome level, analyze its sequence characteristics, evolutionary relationships, and expression patterns under various stresses, and provide candidate genes for stress-tolerant molecular breeding. RESULTS: Based on the LOX conserved domain, an HMM model was constructed, and 11 AkLOX family members were identified from the A. konjac genome. According to catalytic sites, the gene family was classified into three subfamilies: 9-LOX, 13-LOX Type I, and 13-LOX Type II, which were unevenly distributed on 4 chromosomes. The encoded proteins contained 848-945 amino acids with molecular weights ranging from 97,110.54 Da to 102,962.26 Da, all of which were unstable hydrophilic proteins. Phylogenetic and collinearity analyses revealed 6 homologous gene pairs between A. konjac and Amorphophallus albus, one pair between A. konjac and Cucumis sativus/Arabidopsis thaliana, and two pairs between A. konjac and Oryza sativa/Solanum tuberosum, indicating the phylogenetic conservation of the LOX family. Promoter cis-element analysis identified 23 types of cis-regulatory elements, most of which were related to plant growth and development, hormone responses, as well as biotic and abiotic stress responses. qRT-PCR results showed that the expression levels of AkLOX1/4/8 were significantly up-regulated under low temperature, drought, and MeJA treatments, supporting the reliability of the cis-element analysis. Under Pectobacterium carotovorum subsp. carotovorum (Pcc) stress, the expression levels of AkLOX2/3/11 were significantly up-regulated, showing an obvious stress-specific response pattern. CONCLUSIONS: This study performed genome-wide identification and expression analysis of the AkLOX gene family in A. konjac, and clarified their sequence characteristics, evolutionary relationships, and stress response patterns. It was confirmed that members of this gene family are widely involved in biotic and abiotic stress responses in A. konjac, providing candidate genes for subsequent research on A. konjac resistance to Pcc, low temperature, drought and other stresses.