TITLE:
Downregulation of the DST Transcription Factor Using Artificial microRNA to Increase Yield, Salt and Drought Tolerance in Rice
AUTHORS:
Ar-Rafi Md. Faisal, Sudip Biswas, Tasnim Zerin, Tania Rahman, Zeba Islam Seraj
KEYWORDS:
Drought and Salt Tolerance (DST) Transcription Factor, Artificial microRNA Technology, In Planta Transformation, Yield, Stress Tolerance
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.9,
August
17,
2017
ABSTRACT: Abiotic stresses like salinity and drought directly
affect plant growth and water availability, resulting in lower yield in rice.
So, a combination of stress tolerance along with enhanced grain yield is a
major focus of rice breeding. It was reported earlier that loss in function of
the drought and salt tolerance (DST)
gene results in increase in grain production through downregulating Gn1a/OsCKX2 expression.
Moreover, dst mutants also showed enhanced drought and salt tolerance in rice by regulating
genes involved in ROS homeostasis. In the present study, we proceeded to test
these reports by downregulating DST using artificial microRNA technology in the commercial but salt sensitive,
high-yielding, BRRIdhan 28 (BR28). This cultivar was transformed with DST_artificial microRNA (DST_amiRNA) driven by the
constitutive CaMV35S promoter using tissue
culture independent Agrobacterium mediated in planta transformation. DST_amiRNA
transgenic plants were confirmed by artificial microRNA specific PCR.
Transformed plants at T0 generation showed vigorous growth with
significantly longer panicle length and higher primary branching resulting in
higher yield, compared to the wild type (WT) BR28. Semi-quantitative RT PCR
confirmed the decrease in DST expression in the BR28 transgenic plants compared to WT. T1 transgenic
plants also showed improvement in a number of physiological parameters and
greater growth compared to WT after 14 days of 120 mM salt (NaCl) stress at
seedling stage. Therefore, DST downregulated transgenic plants showed both higher stress tolerance as well as
better yields. Furthermore, stable inheritance of the improved phenotype of the
DST_amiRNA
transgenics will be tested in advanced generations.