Final grain weight is not limited by the activity of key starch-synthesising enzymes during grain filling in wheat

A - Papers appearing in refereed journals

Fahy, B., Siddiqui, H., David, L., Powers, S. J., Borrill, P., Uauy, C. and Smith, A. 2018. Final grain weight is not limited by the activity of key starch-synthesising enzymes during grain filling in wheat. Journal of Experimental Botany. 69 (22), p. 5461–5475.

AuthorsFahy, B., Siddiqui, H., David, L., Powers, S. J., Borrill, P., Uauy, C. and Smith, A.
Abstract

Since starch is by far the major component of the mature wheat grain, it has been assumed that variation in the capacity for starch synthesis during grain filling can influence final grain weight. We investigated this assumption by studying a total of 54 wheat genotypes including elite varieties and landraces that were grown in two successive years in fields in the east of England. The weight, water content, sugars, starch, and maximum catalytic activities of two enzymes of starch biosynthesis, ADP-glucose pyrophosphorylase and soluble starch synthase, were measured during grain filling. The relationships between these variables and the weights and starch contents of mature grains were analysed. Final grain weight showed few or no significant correlations with enzyme activities, sugar levels, or starch content during grain filling, or with starch content at maturity. We conclude that neither sugar availability nor enzymatic capacity for starch synthesis during grain filling significantly influenced final grain weight in our field conditions. We suggest that final grain weight may be largely determined by developmental processes prior to grain filling. Starch accumulation then fills the grain to a physical limit set by developmental processes. This conclusion is in accord with those from previous studies in which source or sink strength has been artificially manipulated.

KeywordsField crop; Grain development; Grain weight; Landrace; Starch synthesis; Wheat; Triticum aestivum
Year of Publication2018
JournalJournal of Experimental Botany
Journal citation69 (22), p. 5461–5475
Digital Object Identifier (DOI)doi:10.1093/jxb/ery314
Web address (URL)https://academic.oup.com/jxb/article/69/22/5461/5079202
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeCA508-A09-B
Designing Future Wheat (DFW) [ISPG]
BB/J004596/1
BB/J004561/1
Publisher's version
Output statusPublished
Publication dates
Online25 Aug 2018
Publication process dates
Accepted20 Aug 2018
PublisherOxford University Press (OUP)
Copyright licenseCC BY
ISSN0022-0957

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