Importance of pre-anthesis anther sink strength for maintenance of grain number during reproductive stage water stress in wheat

Xuemei Ji, Behrouz Shiran, Jianlin Wan, David Lewis, Colin Jenkins, Anthony Condon, Richard Richards, Rudy Dolferus

Research output: Contribution to journalArticlepeer-review

167 Citations (Scopus)

Abstract

Reproductive stage water stress leads to spikelet sterility in wheat. Whereas drought stress at anthesis affects mainly grain size, stress at the young microspore stage of pollen development is characterized by abortion of pollen development and reduction in grain number. We identified genetic variability for drought tolerance at the reproductive stage. Drought-tolerant wheat germplasm is able to maintain carbohydrate accumulation in the reproductive organs throughout the stress treatment. Starch depletion in the ovary of drought-sensitive wheat is reversible upon re-watering and cross-pollination experiments indicate that the ovary is more resilient than the anther. The effect on anthers and pollen fertility is irreversible, suggesting that pollen sterility is the main cause of grain loss during drought conditions in wheat. The difference in storage carbohydrate accumulation in drought-sensitive and drought-tolerant wheat is correlated with differences in sugar profiles, cell wall invertase gene expression and expression of fructan biosynthesis genes in anther and ovary (sucrose: sucrose 1-fructosyl-transferase, 1-SST; sucrose: fructan 6-fructosyl-transferase, 6-SFT). Our results indicate that the ability to control and maintain sink strength and carbohydrate supply to anthers may be the key to maintaining pollen fertility and grain number in wheat and this mechanism may also provide protection against other abiotic stresses.

Original languageEnglish
Pages (from-to)926-942
Number of pages17
JournalPlant, Cell and Environment
Volume33
Issue number6
DOIs
Publication statusPublished - Jun 2010
Externally publishedYes

Keywords

  • Cell wall invertase
  • Cereals
  • Drought tolerance
  • Germplasm
  • Pollen sterility
  • Tapetum
  • Young microspore

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