Co-Expression Network Analysis of Soybean Transcriptome Identify Hub Genes Under Saline-Alkaline and Water Deficit Stress.

Background: Soybean is an important oilseed crop that its development and production are affected by environmental stresses (such as saline-alkaline and water deficit).

Objectives: This experiment was performed with the aim of identifying candidate genes in saline-alkaline stress and water-deficit stress conditions using transcriptome analysis and to investigate the expression of these genes under water deficit stress conditions using RTqPCR.

Materials and methods: In this experiment, soybean transcriptome data under saline-alkaline and water-deficit stress were downloaded from the NCBI website, and then the co-expression modules were determined for them and the gene network was plotted for each module, and finally, the hub genes were identified. To compare the expression of genes in saline-alkaline and water deficit conditions, soybean plants were subjected to water deficit stress and their gene expression was determined using RTqPCR.

Results: The filtered (Log FC above +2 and below -2) genes of soybean were grouped under saline-alkaline stress in 15 modules and under water-deficit stress in 2 different modules. Within each module, the interaction of genes was identified using the gene network, then three genes of ann11, cyp450 and zfp selected as hub genes. These hub genes are highly co-expression with other network genes, which not only display differential expression but also differential co-expression. The results of RT-PCR indicated that cyp450 gene expression was not significantly different from the control, while ann11 gene expression significantly increased under water deficit stress, but zfp gene expression decreased significantly under water deficit stress.

Conclusions: We identified three genes, ann11, cyp450 and zfp, as hub genes. According to our results, ann11 gene had a significant increase in expression under water deficit stress, which can indicate the importance of this gene under drought conditions. Therefore, according to the results of this experiment as well as other researchers, we introduce this gene as a key gene in water deficit tolerance and recommend its use in genetic engineering to increase the tolerance of other plants.