INVESTIGATIONS ON ROLE OF SEAWEED BIOFORMULATIONS IN MANAGEMENT OF FUNGICIDAL STRESS AND BLAST DISEASE IN RICE
Loading...
Date
2018-10-30
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BENGALURU
Abstract
Rice is an important food crop cultivated all over the world. India occupies first
and second position in area and production respectively. Fungicidal stress which is
abiotic stress and blast disease a biotic stress, are constrains in the rice production. This
study aimed at managing these stresses through tropical red seaweed (Kappaphycus
alvarezii) bioformulations (LBS-6 and LBD-1). Foliar application of fungicides alone led
to negative physiological changes (stomatal closure and leaf temperature) which were
positive in combinations. Biochemical analysis of ROS, antioxidants and plant minerals
revealed that the seaweed bioformulations alleviated the production of H2O2 and O2
-1
due
to fungicidal stress by inducing the activity of antioxidants viz., APX, CAT, GR, POD
and SOD. Increased levels of Ca+
and K+
interacted with cellular signalling systems of
ROS and stomatal closure respectively. RNA sequencing revealed the growth and
defence related expression of genes in different treatments. A total of 3498 differentially
expressed genes (DEG’s) were identified. Among them 1116 DEG’s were specifically
regulated in MG-01 inoculated treatments. Gene expression using qPCR showed the
increased expression levels of OsPR1#012, OsPR1#021, OsPR1#022, OsPR1#074,
OsPR1#121, PAL-6, PR1-5 and PR-15 transcripts and least disease severity in plants
primed and challenge inoculated with MG-01 under glass house condition. Expression
level of different stress transcripts viz., E2F, HSFA2A, HSFB2B, HSFB4C, HSFC1A and
ZIP12 was less in case of combination treatments compared to sole application of
fungicides. LBD-1 a defence bioformulant was found to be on par with tricyclazole in
curtailing the blast disease under field condition. Increased chlorophyll content, leaf area,
plant height, productive tillers and panicles were recorded in LBS6 treated plants. Results
of tricyclazole residue analysis revealed that, seaweed bioformulations were efficient in
drastic reduction of tricyclazole residue (0.016 mg Kg-1
) in rice grains. Overall growth
and yield parameters directly impacted on straw and grain yield.