Starch synthesis and gelatinization properties of potato tubers

Wang Su,Jian Wang,Yun Zhou,Guangji Ye

doi:10.1590/0103-8478cr20210050

Wang Su, Jian Wang + Show 2 more

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https://doi.org/10.1590/0103-8478cr20210050

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Abstract

ABSTRACT: Biosynthesis is the only source of potato starch which is an important raw material for food processing, modified starch and biomass energy. However, it is not clear about the evolution of starch synthesis with tuber development in potato. The present study evaluated the differences of starch synthesis and gelatinization properties of potato tubers with different starch content. Relative to cultivars of medium and low starch content, cultivars of high starch content showed significantly higher SBEII gene expression, AGPase and SSS enzyme activity, and total starch content after middle stage of starch accumulation, and had smaller average starch granule size during whole process of tuber development, and had higher pasting temperature before late stages of tuber growth, and had lower pasting temperature after middle stage of starch accumulation. Path analysis showed that, after middle stage of starch accumulation, effects on starch gelatinization of cultivars with high, medium and low starch content represented starch synthesis enzyme activity > starch accumulation > starch granule distribution > starch synthesis enzyme gene expression, starch synthesis enzyme gene expression > starch synthesis enzyme activity > starch accumulation > starch granule distribution, starch synthesis enzyme gene expression > starch granule distribution > starch synthesis enzyme activity > starch accumulation, respectively. In the study, phases existed in the starch biosynthesis of potato tuber, and the starch quality and its formation process were different among varieties with different starch content. The findings might contribute to starch application and potato industries.

Highlights

Potato (Solanum tuberosum L.) is the fourth most important food crop in the world, with a total planting area of 20 million hectares and a total yield of 400 million tons globally per annum, following wheat, rice and corn
Activity of starch synthesis key enzyme During S1-S3, the activity of ADP glucose pyrophosphorylase (AGPase), starch synthetase (SSS), starch branching enzyme (SBE) represented MV > HV > LV (P < 0.01, Figure 2A), HV > MV > LV (P < 0.01, Figure 2B), MV > LV > HV (P < 0.01, Figure 2D); there was no significant difference between HV, MV and LV in the activity of granule bound starch synthetase (GBSS) (Figure 2C)
In this study for the first time, we reported that the values and trends for the activity and gene expression of starch synthesis key enzymes, starch accumulation, starch granule distribution and starch gelatinization properties were all significantly different before S3 and after S4 in potato tuber development (Figure 1-2, Table 2-4)

Summary

Introduction

Potato (Solanum tuberosum L.) is the fourth most important food crop in the world, with a total planting area of 20 million hectares and a total yield of 400 million tons globally per annum, following wheat, rice and corn. Melissa Walter planting area of 5.6 million hectares and a total yield of 97 million tons (CHINA NATIONAL BUREAU OF STATISTICS, 2011-2020). When antisense inhibition reduced the expression of AGPase, MÜLLER-RÖBER et al (1992) reported that the starch content of transgenic potato tuber was 4-35% lower than that of wild type. Using patatin promoter drove mutant gene glgc-16 of AGPase, STARK et al (1992) found that the starch content of transgenic potato plants increased by 35% compared with that of wild type. HOVENKAMP-HERMELINK et al (1987) reported that amylose accumulation was significantly decreased in both potato mutant deficient in GBSSI and transgenic potato plant expressing RNAi construct targeting GBSSI. The starch granules structure altered featuring the increase of amylopectin chain length and increase in amylose content when the expression of SBEII was inhibited in potato (JOBLING et al, 1999). While the inhibition of SBEI did not increase amylose content significantly (SAFFORD et al, 1998), the simultaneous down-regulation of both SBEI and SBEII led to 75% increase of amylose content in potato (SCHWALL et al 2000)

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