Aryalekshmi, A S

Molecular screening of rice genotypes for submergence tolerance - Vellayani Department of Plant Biotechnology, College of Agriculture 2018 - 42p.

BSc-MSc (Integrated)

Rice (Oryza sativa L.) is the most important staple food crop that providing food
to about half of the population. One of the major constraints in rice cultivation
worldwide is submergence stress. This mainly affects flood prone areas like
kuttanadu Pokkali as well as low lying paddy fields in Kerala. Sub1 is a major
quatitative trait locus (QTL) representing a cluster of three ethylene responsive
factor (ERF) genes: Sub1A, Sub1B and Sub1C that confers submergence tolerance
to rice genotype. Submergence tolerant rice variety is credited with maintaining
energy and alcoholic fermentation which require high levels of carbohydrates.
Sub1 locus contain Sub1A, Sub1B and Sub1C, all of which are encode ethylene
responsive factor and are up regulated under submergence, but only Sub1A is
responsible for the flash flood tolerance. The near isogenic lines generated by the
introgression of the Sub1 from FR13A into to susceptible cultivar shows restricted
shoot elongation similar to FR13A. Submergence tolerant plants suppress the
expression of gene encoding α- amylase and sucrose synthase, which are involved
in sucrose metabolism. Sub1 A enhance the expression of genes encoding
SLENDER RICE -1 (SLR1) and SLR1 like 1(SLRL1), which are key repressor of
gibberellins (GA) signalling in rice; it also negatively regulate s the GA response
in order to restrict shoot elongation under submergence. Rice varieties with the
Sub1 gene were shown higher survival rate with better yield even after 2 weeks of
submergence stress. The advancement of marker assisted selection (MAS) have
striking impacts on developing improved Sub1 varieties that can meet the
increasing demands of consumers along with population hike. In the present
study, two rice genotypes were observed with Sub1 QTL using SSR markers
through molecular characterization in order to find out the best submergence
tolerant lines. Moreover this finding lays the foundation for further researches
with sub 1 QTL for crop improvement.



Plant Biotechnology

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