Genome-Wide Identification and Characterization of Tomato Fatty Acid β-Oxidase Family Genes KAT and MFP

Abstract

Fatty acids and their derivatives play a variety of roles in living organisms. Fatty acids not only store energy but also comprise membrane lipids and act as signaling molecules. There are three main proteins involved in the fatty acid β-oxidation pathway in plant peroxisomes, including acyl-CoA oxidase (<i>ACX</i>), multifunctional protein (<i>MFP</i>), and 3-ketolipoyl-CoA thiolase (<i>KAT</i>). However, genome-scale analysis of <i>KAT</i> and <i>MFP</i> has not been systemically investigated in tomatoes. Here, we conducted a bioinformatics analysis of <i>KAT</i> and <i>MFP</i> genes in tomatoes. Their physicochemical properties, protein secondary structure, subcellular localization, gene structure, phylogeny, and collinearity were also analyzed. In addition, a conserved motif analysis, an evolutionary pressure selection analysis, a <i>cis</i>-acting element analysis, tissue expression profiling, and a qRT-PCR analysis were conducted within tomato KAT and MFP family members. There are five <i>KAT</i> and four <i>MFP</i> family members in tomatoes, which are randomly distributed on four chromosomes. By analyzing the conserved motifs of tomato <i>KAT</i> and <i>MFP</i> family members, we found that both <i>KAT</i> and <i>MFP</i> members are highly conserved. In addition, the results of the evolutionary pressure selection analysis indicate that the <i>KAT</i> and <i>MFP</i> family members have evolved mainly from purifying selection, which makes them more structurally stable. The results of the <i>cis</i>-acting element analysis show that <i>SlKAT</i> and <i>SlMFP</i> with respect may respond to light, hormones, and adversity stresses. The tissue expression analysis showed that <i>KAT</i> and <i>MFP</i> family members have important roles in regulating the development of floral organs as well as fruit ripening. The qRT-PCR analysis revealed that the expressions of <i>SlKAT</i> and <i>SlMFP</i> genes can be regulated by ABA, MeJA, darkness, NaCl, PEG, UV, cold, heat, and H₂O₂ treatments. These results provide a basis for the involvement of the <i>SlKAT</i> and <i>SlMFP</i> genes in tomato floral organ development and abiotic stress response, which lay a foundation for future functional study of <i>SlKAT</i> and <i>SlMFP</i> in tomatoes.