Reduced ABA accumulation in the root system is caused by ABA exudation in upland rice (Oryza sativa L. var. Gaoshan1) and this enhanced drought adaptation

Lu Shi, Miaomiao Guo, Nenghui Ye, Yinggao Liu, Rui Liu, Yiji XIA, Suxia Cui, Jianhua ZHANG*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Lowland rice (Nipponbare) and upland rice (Gaoshan 1) that are comparable under normal and moderate drought conditions showed dramatic differences in severe drought conditions, both naturally occurring long-term drought and simulated rapid water deficits. We focused on their root response and found that enhanced tolerance of upland rice to severe drought conditions was mainly due to the lower level of ABA in its roots than in those of the lowland rice. We first excluded the effect of ABA biosynthesis and catabolism on root-accumulated ABA levels in both types of rice by monitoring the expression of four OsNCED genes and two OsABA8ox genes. Next, we excluded the impact of the aerial parts on roots by suppressing leaf-biosynthesized ABA with fluridone and NDGA (nordihydroguaiaretic acid), and measuring the ABA level in detached roots. Instead, we proved that upland rice had the ability to export considerably more root-sourced ABA than lowland rice under severe drought, which improved ABA-dependent drought adaptation. The investigation of apoplastic pH in root cells and root anatomy showed that ABA leakage in the root system of upland rice was related to high apoplastic pH and the absence of Casparian bands in the sclerenchyma layer. Finally, taking some genes as examples, we predicted that different ABA levels in rice roots stimulated distinct ABA perception and signaling cascades, which influenced its response to water stress.

Original languageEnglish
Pages (from-to)951-964
Number of pages14
JournalPlant and Cell Physiology
Volume56
Issue number5
DOIs
Publication statusPublished - 2015

Scopus Subject Areas

  • Physiology
  • Plant Science
  • Cell Biology

User-Defined Keywords

  • ABA accumulation
  • Lowland and upland rice
  • pH
  • Root system
  • Sclerenchyma layer
  • Water stress

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