Cyanobacteria Mediated Enhancement of Drought Stress Tolerance in Wheat Genotypes
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Date
2023
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DIVISION OF MICROBIOLOGY ICAR - INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI-110012
Abstract
Drought stress is one of the most serious constraints that limit agricultural productivity
worldwide and affect the food security. Management of drought stress is therefore important
to sustain the agricultural productivity to feed the population. The cyanobacteria are emerging
as potential candidates in this regard. In the present study, experiments were conducted to
assess the desiccation tolerance of Anabaena species. Based on physiological parameters and
multivariate analysis A. fertilissima and A. variablis were identified as most tolerant. Ten
cyanobacterial strains isolated from the desert areas of Pokhran, Rajasthan, India were
identified on the basis of morphological and molecular attributes. The cyanobacterial isolates
Hapalosiphon sp. (SGR2), Nostoc sp. (SGR3), Anabaena sp. (SGR7), Neowestiellopsis sp.
(SGR8) and Fischerella sp. (SGR16) grew optimally at desiccation level (10% w/v
polyethylene glycol). They showed higher activity of antioxidant enzymes, exopolysaccharide
production and plant growth promoting traits. The isolates Nostoc sp. (SGR3) and
Neowestiellopsis sp. (SGR8) were selected for their establishment in liquid and soil microcosm
and these studies did not show any antagonism due to combined inoculation. Neowestiellopsis
sp. (SGR8) exhibited the highest soil chlorophyll content and nitrogenase activity.
A pot experiment was conducted to evaluate the application of Nostoc sp. (SGR3) and
Neowestiellopsis sp. (SGR8) on wheat cultivars. Growth and several of the physiological
parameters were inhibited due to drought stress (25% FC). However, under drought stress
conditions the cyanobacterial inoculation by Neowestiellopsis sp. (SGR8) enhanced the growth
as well as physiological characteristics during the tillering and anthesis stages. Cyanobacterial
inoculation helped the plants to maintain redox status through efficient modulation of
antioxidant enzymes. It was also observed that under drought stress and cyanobacterial
inoculation helped in the maintenance of root system architecture and development of roots.
The cyanobacterial inoculation also improved the soil chemical and biological properties such
as available nitrogen, available phosphorous, dehydrogenase activity and microbial biomass
carbon under drought stress. Improvement in the yield parameters were also recorded in wheat
plants exposed to drought and cyanobacterial inoculation. Protein profiling through twodimensional gel electrophoresis and nano-LC-MS/MS showed the differential expression of
proteins related to drought tolerance due to cyanobacterial inoculation. The overall results show
the potential of cyanobacterial inoculation in the effective management of drought stress in
wheat.