A sucrose non‐fermenting‐1‐related protein kinase‐1 gene, IbSnRK1, improves starch content, composition, granule size, degree of crystallinity and gelatinization in transgenic sweet potato

Abstract

SummarySucrose non-fermenting-1-related protein kinase-1 (SnRK1) is an essential energy-sensing regulator and plays a key role in the global control of carbohydrate metabolism. The SnRK1 gene has been found to increase starch accumulation in several plant species. However, its roles in improving starch quality have not been reported to date. In this study, we found that the IbSnRK1 gene was highly expressed in the storage roots of sweet potato and strongly induced by exogenous sucrose. Its expression followed the circandian rhythm. Its overexpression not only increased starch content, but also decreased proportion of amylose, enlarged granule size and improved degree of crystallinity and gelatinization in transgenic sweet potato, which revealed, for the first time, the important roles of SnRK1 in improving starch quality of plants. The genes involved in starch biosynthesis pathway were systematically up-regulated, and the content of ADP-glucose as an important precursor for starch biosynthesis and the activities of key enzymes were significantly increased in transgenic sweet potato. These findings indicate that IbSnRK1 improves starch content and quality through systematical up-regulation of the genes and the increase in key enzyme activities involved in starch biosynthesis pathway in transgenic sweet potato. This gene has the potential to improve starch content and quality in sweet potato and other plants.

Comparative Transcriptome Profiling Reveals the Genes Involved in Storage Root Expansion in Sweetpotato (Ipomoea batatas (L.) Lam.)

“…The IbSnRK1 (sucrose non-ferment-1-related protein kinase-1) gene can improve the expression level of genes related to the starch biosynthesis pathway and the activities of key enzymes, and affect the starch content of transgenic sweetpotato. Additionally, it is beneficial to improve the quality and yield of sweetpotato [ 33 ]. Therefore, we selected SBEI (starch branching enzyme I), a DEG involved in starch metabolism, from profile 19 of the trend analysis ( Figure 6 A,B).…”

PpSnRK1α overexpression alters the response to light and affects photosynthesis and carbon metabolism in tomato

“…Overexpression of IbSnRK1 in sweet potato increased the assimilation of nitrogen and carbon and improved starch content and quality (Jiang et al, 2013;Ren et al, 2018;Ren et al, 2019). AGPase can convert glucose-1-phosphate (Glc-1-P) into ADP-glucose, which is crucial in the first step of starch synthesis.…”

Engineering Properties of Sweet Potato Starch for Industrial Applications by Biotechnological Techniques including Genome Editing

“…In addition to the metabolic enzymes [26,27], transcription factors [28], stress responsive factors [29,30], and kinases [31] regulate the starch biosynthetic pathway. The involvement of a large number of genes reflects the complexity of starch molecules, amylose/amylopectin ratio, and granular characteristics.…”

“…Sweet potato starch granules are found in various shapes and sizes, from round to polygonal, oval, and semi-oval [61]. The formation of different granules is not only related to growth and agronomic management, but also to the expression of genes, especially those associated with starch biosynthesis [7,22,24,31].…”