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Identification of Putative RuBisCo Activase (TaRca1)-The Catalytic Chaperone Regulating Carbon Assimilatory Pathway in Wheat (Triticum aestivum) under the Heat Stress.

Kumar RR, Goswami S, Singh K, Dubey K, Singh S, Sharma R, Verma N, Kala YK, Rai GK, Grover M, Mishra DC, Singh B, Pathak H, Chinnusamy V, Rai A, Praveen S - Front Plant Sci (2016)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.

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.

No MeSH data available.


Related in: MedlinePlus

Variations in the RuBisCo activity in contrasting wheat cultivars under control (C) and heat stress (HS) conditions at different stages of growth. (A) HD2985 (C and HS), (B) HD2329 (C and HS), (C) Halna (C and HS), (D) PBW621 (C and HS); samples collected from pollination, milky-ripe and mealy-ripe stages were used for the activity assay; C −22 ± 3°, heat stress −42°C for 2 h; NaH14CO3 (20 mM, specific activity 50 mCi mmol−1, BARC, Mumbai) was used for the labeling; different letters above each bar indicate a significant difference (p < 0.05) between the treatments (one-way ANOVA); vertical bars indicate SE (n = 3).
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Figure 7: Variations in the RuBisCo activity in contrasting wheat cultivars under control (C) and heat stress (HS) conditions at different stages of growth. (A) HD2985 (C and HS), (B) HD2329 (C and HS), (C) Halna (C and HS), (D) PBW621 (C and HS); samples collected from pollination, milky-ripe and mealy-ripe stages were used for the activity assay; C −22 ± 3°, heat stress −42°C for 2 h; NaH14CO3 (20 mM, specific activity 50 mCi mmol−1, BARC, Mumbai) was used for the labeling; different letters above each bar indicate a significant difference (p < 0.05) between the treatments (one-way ANOVA); vertical bars indicate SE (n = 3).

Mentions: HD2985 showed maximum RuBisCo activity during mealy-ripe stage, both under control (4.3 nmole CO2/min/mg protein) and HS-treated (2.69 nmole CO2/min/mg protein) conditions (Figure 7A). HS causes decrease in the RuBisCo activity; maximum reduction was observed during pollination stage. In case of HD2329, we observed maximum RuBisCo activity during milky-ripe stage (6.5 nmole CO2/min/mg protein) under control condition and mealy-ripe stage (4 nmole CO2/min/mg protein) under HS-treated condition (Figure 7B). Percent reduction in RuBisCo activity in HD2329 under HS was observed maximum during milky-ripe stage, as compared to other stages of development. Halna showed non-significant differences in the RuBisCo activity estimated in control and HS-treated samples at different stages of development (Figure 7C). PBW621 showed similar pattern of RuBisCo activity as shown by HD2985 under control and HS-treated conditions. Maximum RuBisCo activity was observed during mealy-ripe stage, both under control (5.3 nmole CO2/min/mg protein) and HS-treated (3.5 nmole CO2/min/mg protein) conditions (Figure 7D). Overall, RuBisCO activity was observed maximum in HD2329, both under control and HS-treated conditions at different stages of growth.


Identification of Putative RuBisCo Activase (TaRca1)-The Catalytic Chaperone Regulating Carbon Assimilatory Pathway in Wheat (Triticum aestivum) under the Heat Stress.

Kumar RR, Goswami S, Singh K, Dubey K, Singh S, Sharma R, Verma N, Kala YK, Rai GK, Grover M, Mishra DC, Singh B, Pathak H, Chinnusamy V, Rai A, Praveen S - Front Plant Sci (2016)

Variations in the RuBisCo activity in contrasting wheat cultivars under control (C) and heat stress (HS) conditions at different stages of growth. (A) HD2985 (C and HS), (B) HD2329 (C and HS), (C) Halna (C and HS), (D) PBW621 (C and HS); samples collected from pollination, milky-ripe and mealy-ripe stages were used for the activity assay; C −22 ± 3°, heat stress −42°C for 2 h; NaH14CO3 (20 mM, specific activity 50 mCi mmol−1, BARC, Mumbai) was used for the labeling; different letters above each bar indicate a significant difference (p < 0.05) between the treatments (one-way ANOVA); vertical bars indicate SE (n = 3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940427&req=5

Figure 7: Variations in the RuBisCo activity in contrasting wheat cultivars under control (C) and heat stress (HS) conditions at different stages of growth. (A) HD2985 (C and HS), (B) HD2329 (C and HS), (C) Halna (C and HS), (D) PBW621 (C and HS); samples collected from pollination, milky-ripe and mealy-ripe stages were used for the activity assay; C −22 ± 3°, heat stress −42°C for 2 h; NaH14CO3 (20 mM, specific activity 50 mCi mmol−1, BARC, Mumbai) was used for the labeling; different letters above each bar indicate a significant difference (p < 0.05) between the treatments (one-way ANOVA); vertical bars indicate SE (n = 3).
Mentions: HD2985 showed maximum RuBisCo activity during mealy-ripe stage, both under control (4.3 nmole CO2/min/mg protein) and HS-treated (2.69 nmole CO2/min/mg protein) conditions (Figure 7A). HS causes decrease in the RuBisCo activity; maximum reduction was observed during pollination stage. In case of HD2329, we observed maximum RuBisCo activity during milky-ripe stage (6.5 nmole CO2/min/mg protein) under control condition and mealy-ripe stage (4 nmole CO2/min/mg protein) under HS-treated condition (Figure 7B). Percent reduction in RuBisCo activity in HD2329 under HS was observed maximum during milky-ripe stage, as compared to other stages of development. Halna showed non-significant differences in the RuBisCo activity estimated in control and HS-treated samples at different stages of development (Figure 7C). PBW621 showed similar pattern of RuBisCo activity as shown by HD2985 under control and HS-treated conditions. Maximum RuBisCo activity was observed during mealy-ripe stage, both under control (5.3 nmole CO2/min/mg protein) and HS-treated (3.5 nmole CO2/min/mg protein) conditions (Figure 7D). Overall, RuBisCO activity was observed maximum in HD2329, both under control and HS-treated conditions at different stages of growth.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Division of Biochemistry, Indian Agricultural Research Institute New Delhi, India.

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.

No MeSH data available.


Related in: MedlinePlus