‘Kasalath’ allele in Nipponbare background is responsible for the plasticity in lateral root development of rice under soil moisture fluctuation stress

Issue Date

9-2019

Abstract

Soil moisture fluctuations (SMF) from wet to dry and vice-versa are common under field conditions, which influence root growth and functions and thus dry matter production and yield. In such condition, phenotypic plasticity in L-type lateral root (LLR) development is an adaptive mechanism of rice and the associated quantitative trait locus (QTL) was previously detected in chromosome 12, mainly contributed by the ‘Kasalath’ allele in Nipponbare x Kasalath chromosome segment substitution lines (CSSLs). In this study, we used +qLLRN-12 genotype of Nipponbare background to validate the functions for LR plasticity under SMF and progressive drought. Plants were subjected to well-watered, fluctuations soil moisture and progressive drought conditions for 38 d. There were no significant genotypic differences in shoot growth and root development under well-watered condition. On the other hand, +qLLRN-12 genotype showed greater shoot dry weight by 31% than Nipponbare, which was associated with larger root system of the former than the latter genotype under fluctuating soil moistures. The greater root system development of +qLLRN-12 genotype was attributed to the greater L-type LR development by 95% relative to Nipponbare. However, under progressive drought condition, +qLLRN-12 genotype had reduced shoot dry weight (SDW) due to its smaller root system relative to its fluctuating soil moisture and well-watered counterparts. These results indicate that the introgressed segment of Kasalath on the chromosome 12 region of Nipponbare was responsible for the plasticity in L-type LR, which contributed to greater root system development, increased water uptake and consequently increased dry matter production under fluctuating soil moisture conditions. The findings also suggest that the expression of this allele is unique and triggered only under fluctuating moisture stress conditions.

Source or Periodical Title

The Philippine Agricultural Scientist

ISSN

0031-75454

Volume

102

Issue

3

Page

188-198

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Frequency

quarterly

Physical Description

illustrations; graph; table; references

Language

English

Subject

Roots; rice

En – AGROVOC descriptors

ORYZA SATIVA; RICE; ROOT; ROOT SYSTEM; QUANTITATIVE TRAIT LOCUS; QUANTITATIVE TRAIT LOCI; PHENOTYPIC PLASTICITY; PLASTICITY; SOIL WATER CONTENT; SOIL WATER RETENTION; SOIL WATER DEFICIT; PLANT AVAILABLE WATER

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