Genome-wide identification of BAM genes in grapevine (Vitis vinifera L.) and ectopic expression of VvBAM1 modulating soluble sugar levels to improve low-temperature tolerance in tomato

Abstract

Background Low temperature (LT) is one of the main limiting factors that affect growth and development in grape. Increasing soluble sugar and scavenging reactive oxygen species (ROS) play critical roles in grapevine resistance to cold stress. However, the mechanism of β-amylase (BAM) involved in the regulation of sugar levels and antioxidant enzyme activities in response to cold stress is unclear. Results In this study, six BAM genes were identified and clustered into four groups. Multiple sequence alignment and gene structure analysis showed that VvBAM6 lacked the Glu380 residue and contained only an exon. The transcript abundance of VvBAM1 and VvBAM3 significantly increased as temperature decreased. After LT stress, VvBAM1 was highly expressed in the leaves, petioles, stems, and roots of overexpressing tomato lines. The total amylase and BAM activities increased by 6.5- and 6.01-fold in transgenic plants compared with those in wild-type tomato plants (WT) subjected to LT, respectively. The glucose and sucrose contents in transgenic plants were significantly higher than those in WT plants, whereas the starch contents in the former decreased by 1.5-fold compared with those in the latter under LT stress. The analysis of transcriptome sequencing data revealed that 541 genes were upregulated, and 663 genes were downregulated in transgenic plants. One sugar transporter protein gene (SlSTP10), two peroxidase (POD)-related genes (SlPER7 and SlPER5), and one catalase (CAT)-related gene (SlCAT1) were upregulated by 8.6-, 3.6-, 3.0-, and 2.3-fold in transgenic plants after LT stress, respectively. Conclusions Our results suggest that VvBAM1 overexpression promotes ROS scavenging and improves cold tolerance ability by modulating starch hydrolysis to affect soluble sugar levels in tomato plants.

Genome-wide identification of BAM (β-amylase) gene family in jujube (Ziziphus jujuba Mill.) and expression in response to abiotic stress

“…Phylogenetic analysis of jujube, apple, poplar, cucumber, peach, and A. thaliana revealed that the BAM proteins were evolutionarily conserved. This discovery corroborated the results of BAM phylogenetic tree analyses of A. thaliana , peach, tomato, apple, citrus, strawberry, and pear [ 31 ]. The hydrolytic pathways of starch degradation generally involve AMY, SS, and BAM.…”

“…The metabolic conversion of sugars including glucose, fructose, and sucrose in fresh jujube fruits affects taste and market value [ 29 ]. The BAM genes control sugar degradation and conversion and play various regulatory roles in jujube development and abiotic stress response [ 30 , 31 ]. ZjBAM genes directly or indirectly participate in starch, sucrose, glyoxylate, and dicarboxylate metabolism [ 14 ].…”

“…BAM is a multigene family in several different plant species. Nine BAM genes were identified in A. thaliana [ 18 ], four in rice [ 35 ], nine in barley [ 36 ], 16 in banana [ 37 ], six in grapevine [ 31 ], 30 in Brassica napus , 11 in B. rapa , and 20 in B. oleracea [ 38 ]. Here, we identified nine genes ( ZjBAM1 – ZjBAM9 ) encoding BAM in the jujube genome database.…”

“…Moreover, the expression of BnaBAM3 and BnaBAM5 is significantly upregulated in Brassica under heat stress [ 38 ]. Meanwhile, VvBAM1 overexpression in tomatoes alters the soluble sugar levels and improves cold tolerance [ 31 ]. The expression of CsBAM gene family members is significantly upregulated in Camellia sinensis under ABA, salt, drought, and cold stress [ 17 ].…”

Genome-wide characterization and expression analysis of α-amylase and β-amylase genes underlying drought tolerance in cassava

“…Under drought stress, soybean leaves contained less starch and more soluble sugar, and that the expression levels of the genes GmAMY3 and GmBAM1 also altered dramatically [14]. Recent research has shown that VvBAM1 improves plant cold tolerance by controlling starch hydrolysis, promoting reactive oxygen species (ROS), and scavenging in VvBAM1 over-expression transgenic tomato plants [15].…”