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This content will become publicly available on May 31, 2024

Title: Targeted mutagenesis of the vacuolar H + translocating pyrophosphatase gene reduces grain chalkiness in rice
SUMMARY

Grain chalkiness is a major concern in rice production because it impacts milling yield and cooking quality, eventually reducing market value of the rice. A gene encoding vacuolar H+translocating pyrophosphatase (V‐PPase) is a major quantitative trait locus inindicarice, controlling grain chalkiness. Higher transcriptional activity of this gene is associated with increased chalk content. However, whether the suppression ofV‐PPasecould reduce chalkiness is not clear. Furthermore, natural variation in the chalkiness ofjaponicarice has not been linked withV‐PPase. Here, we describe promoter targeting of thejaponica V‐PPaseallele that led to reduced grain chalkiness and the development of more translucent grains. Disruption of a putative GATA element by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated protein 9 suppressedV‐PPaseactivity, reduced grain chalkiness and impacted post‐germination growth that could be rescued by the exogenous supply of sucrose. The mature grains of the targeted lines showed a much lower percentage of large or medium chalk. Interestingly, the targeted lines developed a significantly lower chalk under heat stress, a major inducer of grain chalk. Metabolomic analysis showed that pathways related to starch and sugar metabolism were affected in the developing grains of the targeted lines that correlated with higher inorganic pyrophosphate and starch contents and upregulation of starch biosynthesis genes. In summary, we show a biotechnology approach of reducing grain chalkiness in rice by downregulating the transcriptional activity ofV‐PPasethat presumably leads to altered metabolic rates, including starch biosynthesis, resulting in more compact packing of starch granules and formation of translucent rice grains.

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Award ID(s):
1826836
NSF-PAR ID:
10421831
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
The Plant Journal
Volume:
115
Issue:
5
ISSN:
0960-7412
Page Range / eLocation ID:
p. 1261-1276
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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