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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

Changes in the non-reducing sugar accumulation in stem and leaves of wheat cvs. under control and heat stress conditions. (A,B) Non-reducing sugar content in stem and leaf of HD2329, (C,D) Non-reducing sugar accumulation in stem and leaf of PBW621, (E,F) Non-reducing sugar content in stem and leaf of Halna, (G,H) Non-reducing sugar accumulation in stem and leaf of HD2985. Thermosusceptible (HD2329 and PBW621) and thermotolerant (Halna and HD2985) were used for the non-reducing sugar accumulation pattern analysis; C −22 ± 3°, heat stress –42°C for 2 h; Milky-ripe and mealy-ripe sub-stages of grain-filling were used for the analysis; 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 10: Changes in the non-reducing sugar accumulation in stem and leaves of wheat cvs. under control and heat stress conditions. (A,B) Non-reducing sugar content in stem and leaf of HD2329, (C,D) Non-reducing sugar accumulation in stem and leaf of PBW621, (E,F) Non-reducing sugar content in stem and leaf of Halna, (G,H) Non-reducing sugar accumulation in stem and leaf of HD2985. Thermosusceptible (HD2329 and PBW621) and thermotolerant (Halna and HD2985) were used for the non-reducing sugar accumulation pattern analysis; C −22 ± 3°, heat stress –42°C for 2 h; Milky-ripe and mealy-ripe sub-stages of grain-filling were used for the analysis; 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: HD2329 showed maximum accumulation of non-reducing sugar in stem during mealy-ripe under control (27 mg/g FW) condition, which drastically decrease under HS (10 mg/g FW) (Figure 10). Similar pattern of non-reducing sugar accumulation was observed in stem of PBW621 under control and HS-treated conditions. Halna showed maximum accumulation of non-reducing sugar in stem during milky-ripe stage (11.5 mg/g FW) under control condition (Figure 10). We observed significant decrease in the non-reducing sugar accumulation in stem of PBW621 under HS at different sub-stages of grain-filling. Non-reducing sugar accumulation was observed minimum in stem of HD2985 compared to other cvs., both at milky- and mealy-ripe stages under control and HS-treated conditions. Non-reducing sugar content in leaves of HD2329 showed maximum accumulation during mealy-ripe stage under control and HS-treated conditions. Non-significant variations in the non-reducing sugar accumulation were observed in PBW621 under control and HS-treated conditions. Halna showed maximum accumulation of non-reducing sugar in leaves during milky-ripe, both under control and HS-treated conditions, which reduces subsequently during mealy-ripe stage. Similar pattern of non-reducing sugar accumulation in leaves of HD2985 was observed under control and HS-treated conditions (Figure 10). Non-reducing sugar in leaves of HD2985 decreased significantly under the control and HS-treated conditions during the grain-filling; decrease was more during the milky-ripe stage.


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)

Changes in the non-reducing sugar accumulation in stem and leaves of wheat cvs. under control and heat stress conditions. (A,B) Non-reducing sugar content in stem and leaf of HD2329, (C,D) Non-reducing sugar accumulation in stem and leaf of PBW621, (E,F) Non-reducing sugar content in stem and leaf of Halna, (G,H) Non-reducing sugar accumulation in stem and leaf of HD2985. Thermosusceptible (HD2329 and PBW621) and thermotolerant (Halna and HD2985) were used for the non-reducing sugar accumulation pattern analysis; C −22 ± 3°, heat stress –42°C for 2 h; Milky-ripe and mealy-ripe sub-stages of grain-filling were used for the analysis; 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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Related In: Results  -  Collection

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Figure 10: Changes in the non-reducing sugar accumulation in stem and leaves of wheat cvs. under control and heat stress conditions. (A,B) Non-reducing sugar content in stem and leaf of HD2329, (C,D) Non-reducing sugar accumulation in stem and leaf of PBW621, (E,F) Non-reducing sugar content in stem and leaf of Halna, (G,H) Non-reducing sugar accumulation in stem and leaf of HD2985. Thermosusceptible (HD2329 and PBW621) and thermotolerant (Halna and HD2985) were used for the non-reducing sugar accumulation pattern analysis; C −22 ± 3°, heat stress –42°C for 2 h; Milky-ripe and mealy-ripe sub-stages of grain-filling were used for the analysis; 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: HD2329 showed maximum accumulation of non-reducing sugar in stem during mealy-ripe under control (27 mg/g FW) condition, which drastically decrease under HS (10 mg/g FW) (Figure 10). Similar pattern of non-reducing sugar accumulation was observed in stem of PBW621 under control and HS-treated conditions. Halna showed maximum accumulation of non-reducing sugar in stem during milky-ripe stage (11.5 mg/g FW) under control condition (Figure 10). We observed significant decrease in the non-reducing sugar accumulation in stem of PBW621 under HS at different sub-stages of grain-filling. Non-reducing sugar accumulation was observed minimum in stem of HD2985 compared to other cvs., both at milky- and mealy-ripe stages under control and HS-treated conditions. Non-reducing sugar content in leaves of HD2329 showed maximum accumulation during mealy-ripe stage under control and HS-treated conditions. Non-significant variations in the non-reducing sugar accumulation were observed in PBW621 under control and HS-treated conditions. Halna showed maximum accumulation of non-reducing sugar in leaves during milky-ripe, both under control and HS-treated conditions, which reduces subsequently during mealy-ripe stage. Similar pattern of non-reducing sugar accumulation in leaves of HD2985 was observed under control and HS-treated conditions (Figure 10). Non-reducing sugar in leaves of HD2985 decreased significantly under the control and HS-treated conditions during the grain-filling; decrease was more during the milky-ripe stage.

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