Overexpression of a Sucrose Synthase Gene Indirectly Improves Cotton Fiber Quality Through Sucrose Cleavage

Abstract

The study aims to improve fiber traits of local cotton cultivar through genetic transformation of sucrose synthase ( SuS ) gene in cotton. Sucrose synthase (SuS) is an important factor that is involved in the conversion of sucrose to fructose and UDP-glucose, which are essential for the synthesis of cell wall cellulose. In the current study, we expressed a synthetic SuS gene in cotton plants under the control of a CaMV35S promoter. Amplification of an 813-bp fragment using gene-specific primers confirmed the successful introduction of SuS gene into the genome of cotton variety CEMB-00. High SuS mRNA expression was observed in two transgenic cotton plants, MA0023 and MA0034, when compared to the expression in two other transgenic cotton plants, MA0035 and MA0038. Experiments showed that SuS mRNA expression was positively correlated with SuS activity at the vegetative (54%) and reproductive stages (40%). Furthermore, location of transgene was found to be at chromosome no. 9 in the form of single insertion, while no signal was evident in non-transgenic control cotton plant when evaluated through fluorescent in situ hybridization and karyotyping analysis. Fiber analyses of the transgenic cotton plants showed increases of 11.7% fiber length, 18.65% fiber strength, and up to 5% cellulose contents. An improvement in the micronaire value of 4.21 was also observed in the MA0038 transgenic cotton line. Scanning electron microscopy (SEM) revealed that the fibers of the SuS transgenic cotton plants were highly spiral with a greater number of twists per unit length than the fibers of the non-transgenic control plants. These results determined that SuS gene expression influenced cotton fiber structure and quality, suggesting that SuS gene has great potential for cotton fiber quality improvement.

Transformation and Overexpression of Primary Cell Wall Synthesis-Related Zinc Finger Gene Gh_A07G1537 to Improve Fiber Length in Cotton

“…It was found that MBI7747 showed an SNP and a complete Indel of 55 bp than its parents CCRI45 and Hai1. This finding strengthens the previous hypothesis that this gene might contribute a significant addition to the improvement of fiber length just like other transgenes such as expansin (Bajwa et al, 2015), cellulose synthase (Arioli et al, 1998), sucrose synthase (Ahmed et al, 2020), and actin (Ahmed et al, 2018a).…”

“…For example, CaMV35S promoter is widely adopted and reported efficient transformation of foreign gene into the cotton plant. In a recent study of sucrose synthase (SuS) gene transformation in cotton, CaMV35S promoter is used and resulted in significant improvement in fiber quality (Ahmed et al, 2020). This has been proved through various studies that revealed the relative expression of the tissue specific and constitutive promoters.…”

“…The qualitative and quantitative traits of the cotton fiber are significantly regulated by the genes involved in cell wall synthesis and extension (Guo et al, 2016). Several genes and transcription factors for expansin (Bajwa et al, 2015), cellulose synthase (Arioli et al, 1998), sucrose synthase (Ahmed et al, 2020), and actin have been transformed successfully into cotton for the improvement of fiber quality and yield (Ahmed et al, 2018a).…”

The hexokinase Gene Family in Cotton: Genome-Wide Characterization and Bioinformatics Analysis

“… Jiang et al (2012) demonstrated that over-expressing GhsusA1 , a cotton SuSy gene, increased the thickness of the secondary cell wall and overall fiber strength, which indicates that a sucrose signal is involved in controlling cellulose biosynthesis in the development of cotton fiber ( Jiang et al, 2012 ). When this synthetic SuS y gene is overexpressed in cotton, the transgenic cotton plants showed longer fiber length, enhanced fiber strength, and increased cellulose contents ( Ahmed et al, 2020 ). The cell wall invertase (CWIN) is responsible for sucrose cleaving into fructose and glucose, while the expression levels of GhCWIN are significantly more highly expressed at 5 and 10 DPA than 15 and 20 DPA ( Wang and Ruan, 2012 ).…”

Advances about the Roles of Membranes in Cotton Fiber Development

“…The suppression of GhSusA1 led to reduced fiber quality, boll size, and seed weight, while the overexpression of this gene increased fiber length and strength [ 59 ]. In addition, the overexpression of a potato SuSy and a synthetic SuSy gene also improved cotton fiber quality [ 60 , 61 ]. Therefore, PM-associated SuSy are important for cotton fiber development, and could be used for improving fiber products.…”