A genome-wide expression analysis ofriceroot tips from two varieties
helped scientists identify candidate genesfor water stress adaptation.
The two varieties reacted differently to water stress, providing more
options for candidate genes potentially involved in root system
architecture modification to be investigated further.

A team of scientists from Iran andAustraliaanalyzed the transcriptome
response of rice root tips to water stress using IR64 and Azucena
varieties. IR64, a high-yielding lowland variety, was chosen to
represent a drought-susceptible and shallow-rooting genotype. On the
other hand, Azucena is a traditional upland variety and represented a
drought-tolerant, deep-rooting genotype. Samples from three root zones
were collected from each variety at 35 days which were first subjected
to water stress for 14 days.

Phenotypically, the scientists found that Azucena avoided water stress
through enhancing growth and root exploration to access water, while
IR64 had a shallow root system that mainly relied on cell insulation and
an antioxidant system to resist stress. Detailed analyses of the
transcriptome responses of the three root tip zones from the two
contrasting varieties enabled the scientists to identify several
differentially expressed genes and differential pathways related to root
systems architecture and water stress adaptation. They found that
several members of gene families such as NAC, AP2/ERF, AUX/IAA,
EXPANSIN, WRKY, and MYB were key players in root systems architecture
and drought adaptation, while HSP and HSF gene families were important
in oxidative stress inhibition. The number of novel root system
architecture and drought-associated genes that the scientists were able
to identify can help other research programs to investigate their
potential to enhance drought tolerance adaptation in rice.

Frontiers | Genome-Wide Expression Analysis of Root Tips in Contrasting
Rice Genotypes Revealed Novel Candidate Genes for Water Stress
Adaptation | Plant Science (frontiersin.org)
[www.frontiersin.org]