title: Identification of Putative RuBisCo Activase (TaRca1)-The Catalytic Chaperone Regulating Carbon Assimilatory Pathway in Wheat (Triticum aestivum) under the Heat Stress.
abstract: RuBisCo activase (Rca) is a catalytic chaperone involved in modulating the activity of RuBisCo (key enzyme of photosynthetic pathway). Here, we identified eight novel transcripts from wheat through data mining predicted to be Rca and cloned a transcript of 1.4 kb from cv. HD2985, named as TaRca1 (GenBank acc. no. KC776912). Single copy number of TaRca1 was observed in wheat genome. Expression analysis in diverse wheat genotypes (HD2985, Halna, PBW621, and HD2329) showed very high relative expression of TaRca1 in Halna under control and HS-treated, as compared to other cultivars at different stages of growth. TaRca1 protein was predicted to be chloroplast-localized with numerous potential phosphorylation sites. Northern blot analysis showed maximum accumulation of TaRca1 transcript in thermotolerant cv. during mealy-ripe stage, as compared to thermosusceptible. Decrease in the photosynthetic parameters was observed in all the cultivars, except PBW621 in response to HS. We observed significant increase in the Rca activity in all the cultivars under HS at different stages of growth. HS causes decrease in the RuBisCo activity; maximum reduction was observed during pollination stage in thermosusceptible cvs. as validated through immunoblotting. We observed uniform carbon distribution in different tissues of thermotolerant cvs., as compared to thermosusceptible. Similarly, tolerance level of leaf was observed maximum in Halna having high Rca activity under HS. A positive correlation was observed between the transcript and activity of TaRca1 in HS-treated Halna. Similarly, TaRca1 enzyme showed positive correlation with the activity of RuBisCo. There is, however, need to manipulate the thermal stability of TaRca1 enzyme through protein engineering for sustaining the photosynthetic rate under HS-a novel approach toward development of "climate-smart" crop.
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Ranjeet R
authors.initials: RR
authors.lastname: Kumar
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Suneha
authors.initials: S
authors.lastname: Goswami
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Khushboo
authors.initials: K
authors.lastname: Singh
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Kavita
authors.initials: K
authors.lastname: Dubey
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Shweta
authors.initials: S
authors.lastname: Singh
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Renu
authors.initials: R
authors.lastname: Sharma
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Verma
authors.affiliation: Division of Genetics, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Yugal K
authors.initials: YK
authors.lastname: Kala
authors.affiliation: School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology Jammu, India.
authors.forename: Gyanendra K
authors.initials: GK
authors.lastname: Rai
authors.affiliation: Centre for Agricultural Bioinformatics, Indian Council of Agricultural Research-Indian Agricultural Statistics Research Institute New Delhi, India.
authors.forename: Monendra
authors.initials: M
authors.lastname: Grover
authors.affiliation: Centre for Agricultural Bioinformatics, Indian Council of Agricultural Research-Indian Agricultural Statistics Research Institute New Delhi, India.
authors.forename: Dwijesh C
authors.initials: DC
authors.lastname: Mishra
authors.affiliation: Nuclear Research Laboratory, Plant Physiology, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Bhupinder
authors.initials: B
authors.lastname: Singh
authors.affiliation: Center for Environment Science and Climate Resilient Agriculture, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Pathak
authors.affiliation: Division of Plant Physiology, Indian Council of Agricultural Research-Indian Agricultural Research Institute New Delhi, India.
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Chinnusamy
authors.affiliation: Centre for Agricultural Bioinformatics, Indian Council of Agricultural Research-Indian Agricultural Statistics Research Institute New Delhi, India.
authors.forename: Anil
authors.initials: A
authors.lastname: Rai
authors.affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.
authors.forename: Shelly
authors.initials: S
authors.lastname: Praveen
keywords: IRGA; RuBisCo; RuBisCo activase; carbon partitioning; heat stress; photosynthesis; qRT-PCR; wheat