Genetic Analysis of the Peach SnRK1β3 Subunit and Its Function in Transgenic Tomato Plants

Abstract

Background/objectives: The sucrose non-fermentation-related kinase 1 (SnRK1) protein complex in plants plays an important role in energy metabolism, anabolism, growth, and stress resistance. SnRK1 is a heterotrimeric complex. The SnRK1 complex is mainly composed of α, β, βγ, and γ subunits. Studies on plant SnRK1 have primarily focused on the functional α subunit, with the β regulatory subunit remaining relatively unexplored. The present study aimed to elucidate the evolutionary relationship, structural prediction, and interaction with the core α subunit of peach SnRK1β3 (PpSnRK1) subunit.

Methods: Bioinformatics analysis of PpSnRK1 was performed through software and website. We produced transgenic tomato plants overexpressing PpSnRK1 (OEPpSnRK1). Transcriptome analysis was performed on OEPpSnRK1 tomatoes. We mainly tested the growth index and drought resistance of transgenic tomato plants.

Results: The results showed that PpSnRK1 has a 354 bp encoded protein sequence (cds), which is mainly located in the nucleus and cell membrane. Phylogenetic tree analysis showed that PpSnRK1β3 has similar domains to other woody plants. Transcriptome analysis of OEPpSnRK1β3 showed that PpSnRK1β3 is widely involved in biosynthetic and metabolic processes. Functional analyses of these transgenic plants revealed prolonged growth periods, enhanced growth potential, improved photosynthetic activity, and superior drought stress tolerance.

Conclusions: The study findings provide insight into the function of the PpSnRK1 subunit and its potential role in regulating plant growth and drought responses. This comprehensive analysis of PpSnRK1 will contribute to further enhancing our understanding of the plant SnRK1 protein complex.

Keywords: PpSnRK1β3; peach; transgenic tomato plants.

Figure 1

Length, structure prediction, and subcellular localization of PpSnRK1β3. (a) The cds length electropherogram of PpSnRK1β3. (b) Spatial structure prediction of PpSnRK1β3. (c) Subcellular localization of PpSnRK1β3.

Figure 2

Phylogenetic tree analysis of PpSnRK1β3. (a) Phylogenetic tree analysis of the SnRK1β3 protein in different species. (b) Sequence alignment of the SnRK1β3 protein from different species.

Figure 3

Interaction between the PpSnRK1β3 and PpSnRK1α subunits. (a) Yeast two-hybrid assay of PpSnRK1β3 and PpSnRK1α. (b) Bimolecular fluorescence complementation (BiFC) assay of PpSnRK1β3 and PpSnRK1α. (c) Dual luciferase assay of PpSnRK1β3 and PpSnRK1α.

Figure 4

GO enrichment analysis of the comparison between OEPpSnRK1β3 and WT tomatoes. DEGs were selected based on a cut-off of p-adjust  <  0.05 and |log2FC| ≥ 1, p-adjust lists the top 20 enrichments in ascending order. (a–c) Downregulated WT genes were associated with biological processes, cellular components, and molecular functions in GO enrichment compared with the OEPpSnRK1β3 tomatoes. (d–f) WT upregulated in biological processes, cellular components, and molecular functions in GO enrichment compared with the OEPpSnRK1β3 tomatoes.

Figure 5

KEGG enrichment analysis of the comparison between OEPpSnRK1β3 and WT tomatoes. DEGs were selected based on a cut-off of p-adjust  <  0.05 and |log2FC| ≥ 1; p-adjust lists the top 20 enrichments in ascending order. (a) Downregulated WT genes by KEGG enrichment compared with OEPpSnRK1β3 tomatoes. (b) Upregulated WT genes by KEGG enrichment compared with OEPpSnRK1β3 tomatoes.

Figure 6

Growth characteristics of the OEPpSnRK1β3 tomatoes. (a) Growth period of OEPpSnRK1β3 and WT tomatoes (white line in the diagram indicates the height of 1 cm). (b) Fruit development period of OEPpSnRK1β3 and WT tomatoes (white line in the diagram indicates the length of 1 cm). Comparison of plant height (c), stem diameter (d), leaf area (e), and number of days in the growth period (f) for three strains of OEPpSnRK1β3 and WT tomatoes. Error bars represent the means ± SD (n = 3) from three independent biological replicates. Note: For (c–f), asterisks represent significant differences (LSD test, *, p < 0.05).

Figure 7

Photosynthetic indicators of OEPpSnRK1β3 tomatoes. Comparison of maximum net photosynthetic efficiency (a), chlorophyll content (b), stomatal conductance (c), and intercellular carbon dioxide concentration (d) for three strains of OEPpSnRK1β3 and WT tomatoes. Error bars represent the means ± SD (n = 3) from three independent biological replicates. Asterisks represent significant differences (LSD test, *, p < 0.05; **, p < 0.01).

Figure 8

Physiological indexes of stress in OEPpSnRK1β3 tomatoes under drought stress. (a) The state of OEPpSnRK1β3 and WT tomatoes under normal and 14-day drought stress. Comparison of maximum photochemical efficiency (b), malondialdehyde content (c), hydrogen peroxide content (d), superoxide anion content (e), and relative electrolyte leakage (f) for three strains of OEPpSnRK1β3 and WT tomatoes under normal and 14-day drought stress conditions. Error bars represent the means ± SD (n = 3) from three independent biological replicates. Note: For (b–f), asterisks represent significant differences (LSD test, *, p < 0.05; **, p < 0.01).