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Expression profiling of abiotic stress-inducible genes in response to multiple stresses in rice (Oryza sativa L.) varieties with contrasting level of stress tolerance.

Basu S, Roychoudhury A - Biomed Res Int (2014)

Bottom Line: Heat map data also showed differential transcript abundance in the three varieties, correlating the observation with transcript profiling.In silico analysis of the upstream regions of all the genes represented the existence of conserved sequence motifs in single or multiple copies that are indispensable to abiotic stress response.The present work will pave the way in future to select gene(s) for overexpression, so as to generate broad spectrum resistance to multiple stresses simultaneously.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop, Soil, and Environmental Sciences, University of Arkansas, 115 Plant Sciences Building, Fayetteville, AR 72701, USA.

ABSTRACT
The present study considered transcriptional profiles and protein expression analyses from shoot and/or root tissues under three abiotic stress conditions, namely, salinity, dehydration, and cold, as well as following exogenous abscisic acid treatment, at different time points of stress exposure in three indica rice varieties, IR-29 (salt sensitive), Pokkali, and Nonabokra (both salt tolerant). The candidate genes chosen for expression studies were HKT-1, SOS-3, NHX-1, SAPK5, SAPK7, NAC-1, Rab16A, OSBZ8, DREBP2, CRT/DREBP, WRKY24, and WRKY71, along with the candidate proteins OSBZ8, SAMDC, and GST. Gene expression profile revealed considerable differences between the salt-sensitive and salt-tolerant rice varieties, as the expression in the latter was higher even at the constitutive level, whereas it was inducible only by corresponding stress signals in IR-29. Whether in roots or shoots, the transcriptional responses to different stressors peaked following 24 h of stress/ABA exposure, and the transcript levels enhanced gradually with the period of exposure. The generality of stress responses at the transcriptional level was therefore time dependent. Heat map data also showed differential transcript abundance in the three varieties, correlating the observation with transcript profiling. In silico analysis of the upstream regions of all the genes represented the existence of conserved sequence motifs in single or multiple copies that are indispensable to abiotic stress response. Overall, the transcriptome and proteome analysis undertaken in the present study indicated that genes/proteins conferring tolerance, belonging to different functional classes, were overrepresented, thus providing novel insight into the functional basis of multiple stress tolerance in indica rice varieties. The present work will pave the way in future to select gene(s) for overexpression, so as to generate broad spectrum resistance to multiple stresses simultaneously.

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Related in: MedlinePlus

Semiquantitative RT-PCR analysis showing differential gene expression in leaf tissues (a) and roots (b) of 12-day-old seedlings of IR-29 (salt sensitive), Pokkali and Nonabokra (both salt tolerant) rice cultivars in response to PEG (20%)-mediated dehydration; stress was imposed for 6/24 hours to detect the transcript level in leaves, whereas for roots, the durations of stress treatment were 24 hours (in IR-29 and Pokkali) and 6/24 hours (in Nonabokra); the expression of each gene was compared relative to its expression in control C (untreated) sample (0 h).
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fig3: Semiquantitative RT-PCR analysis showing differential gene expression in leaf tissues (a) and roots (b) of 12-day-old seedlings of IR-29 (salt sensitive), Pokkali and Nonabokra (both salt tolerant) rice cultivars in response to PEG (20%)-mediated dehydration; stress was imposed for 6/24 hours to detect the transcript level in leaves, whereas for roots, the durations of stress treatment were 24 hours (in IR-29 and Pokkali) and 6/24 hours (in Nonabokra); the expression of each gene was compared relative to its expression in control C (untreated) sample (0 h).

Mentions: With dehydration stress, especially the transcripts of SOS-3, SAPK5, and OSBZ8 were greatly accumulated in the leaves of all the varieties; the maximum accumulation being recorded after 24 h of stress in both IR-29 and Pokkali, although the induction over control was higher for the salt-sensitive variety for all the genes except HKT-1. Nonabokra exhibited constitutive expression of all the genes, with lesser inducibility. The MADS6 gene showed no variation in expression with dehydration stress, as compared to control (Figure 3(a)). In case of roots, HKT-1, SOS-3, SAPK5, OSBZ8, and CRT/DREBP showed better inducibility with dehydration stress. Moreover, all the genes, except DREBP2, showed higher expression in Pokkali and Nonabokra, following 24 h stress treatment, although the induction over control was sharper in IR-29. The genes SAPK7, Rab16A, NAC-1, and DREBP2 showed very weak response to dehydration stress in roots. The MADS6 gene expression was almost unaffected by stress (Figure 3(b)).


Expression profiling of abiotic stress-inducible genes in response to multiple stresses in rice (Oryza sativa L.) varieties with contrasting level of stress tolerance.

Basu S, Roychoudhury A - Biomed Res Int (2014)

Semiquantitative RT-PCR analysis showing differential gene expression in leaf tissues (a) and roots (b) of 12-day-old seedlings of IR-29 (salt sensitive), Pokkali and Nonabokra (both salt tolerant) rice cultivars in response to PEG (20%)-mediated dehydration; stress was imposed for 6/24 hours to detect the transcript level in leaves, whereas for roots, the durations of stress treatment were 24 hours (in IR-29 and Pokkali) and 6/24 hours (in Nonabokra); the expression of each gene was compared relative to its expression in control C (untreated) sample (0 h).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109260&req=5

fig3: Semiquantitative RT-PCR analysis showing differential gene expression in leaf tissues (a) and roots (b) of 12-day-old seedlings of IR-29 (salt sensitive), Pokkali and Nonabokra (both salt tolerant) rice cultivars in response to PEG (20%)-mediated dehydration; stress was imposed for 6/24 hours to detect the transcript level in leaves, whereas for roots, the durations of stress treatment were 24 hours (in IR-29 and Pokkali) and 6/24 hours (in Nonabokra); the expression of each gene was compared relative to its expression in control C (untreated) sample (0 h).
Mentions: With dehydration stress, especially the transcripts of SOS-3, SAPK5, and OSBZ8 were greatly accumulated in the leaves of all the varieties; the maximum accumulation being recorded after 24 h of stress in both IR-29 and Pokkali, although the induction over control was higher for the salt-sensitive variety for all the genes except HKT-1. Nonabokra exhibited constitutive expression of all the genes, with lesser inducibility. The MADS6 gene showed no variation in expression with dehydration stress, as compared to control (Figure 3(a)). In case of roots, HKT-1, SOS-3, SAPK5, OSBZ8, and CRT/DREBP showed better inducibility with dehydration stress. Moreover, all the genes, except DREBP2, showed higher expression in Pokkali and Nonabokra, following 24 h stress treatment, although the induction over control was sharper in IR-29. The genes SAPK7, Rab16A, NAC-1, and DREBP2 showed very weak response to dehydration stress in roots. The MADS6 gene expression was almost unaffected by stress (Figure 3(b)).

Bottom Line: Heat map data also showed differential transcript abundance in the three varieties, correlating the observation with transcript profiling.In silico analysis of the upstream regions of all the genes represented the existence of conserved sequence motifs in single or multiple copies that are indispensable to abiotic stress response.The present work will pave the way in future to select gene(s) for overexpression, so as to generate broad spectrum resistance to multiple stresses simultaneously.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop, Soil, and Environmental Sciences, University of Arkansas, 115 Plant Sciences Building, Fayetteville, AR 72701, USA.

ABSTRACT
The present study considered transcriptional profiles and protein expression analyses from shoot and/or root tissues under three abiotic stress conditions, namely, salinity, dehydration, and cold, as well as following exogenous abscisic acid treatment, at different time points of stress exposure in three indica rice varieties, IR-29 (salt sensitive), Pokkali, and Nonabokra (both salt tolerant). The candidate genes chosen for expression studies were HKT-1, SOS-3, NHX-1, SAPK5, SAPK7, NAC-1, Rab16A, OSBZ8, DREBP2, CRT/DREBP, WRKY24, and WRKY71, along with the candidate proteins OSBZ8, SAMDC, and GST. Gene expression profile revealed considerable differences between the salt-sensitive and salt-tolerant rice varieties, as the expression in the latter was higher even at the constitutive level, whereas it was inducible only by corresponding stress signals in IR-29. Whether in roots or shoots, the transcriptional responses to different stressors peaked following 24 h of stress/ABA exposure, and the transcript levels enhanced gradually with the period of exposure. The generality of stress responses at the transcriptional level was therefore time dependent. Heat map data also showed differential transcript abundance in the three varieties, correlating the observation with transcript profiling. In silico analysis of the upstream regions of all the genes represented the existence of conserved sequence motifs in single or multiple copies that are indispensable to abiotic stress response. Overall, the transcriptome and proteome analysis undertaken in the present study indicated that genes/proteins conferring tolerance, belonging to different functional classes, were overrepresented, thus providing novel insight into the functional basis of multiple stress tolerance in indica rice varieties. The present work will pave the way in future to select gene(s) for overexpression, so as to generate broad spectrum resistance to multiple stresses simultaneously.

Show MeSH
Related in: MedlinePlus