Recent advances in next generation sequencing have created opportunities to directly identify gen... more Recent advances in next generation sequencing have created opportunities to directly identify genetic loci and candidate genes for abiotic stress responses in plants. With the objective of identifying candidate genes within the previously identified QTL-hotspots, the whole genomes of two divergent cultivars for salt responses, namely At 354 and Bg 352, were re-sequenced using Illumina Hiseq 2500 100PE platform and mapped to Nipponbare and R498 genomes. The sequencing results revealed approximately 2.4 million SNPs and 0.2 million InDels with reference to Nipponbare while 1.3 million and 0.07 million with reference to R498 in two parents. In total, 32,914 genes were reported across all rice chromosomes of this study. Gene mining within QTL hotspots revealed 1236 genes, out of which 106 genes were related to abiotic stress. In addition, 27 abiotic stress-related genes were identified in non-QTL regions. Altogether, 32 genes were identified as potential genes containing polymorphic non...
Traditionally majority of the rural farming community in Sri Lanka rely on agriculture extension ... more Traditionally majority of the rural farming community in Sri Lanka rely on agriculture extension officers for advice, guidance and training opportunities on crop cultivation, particularly due to government assistance schemes in agriculture. Ongoing COL-L3F project implemented by the Open University of Sri Lanka (OUSL) recognized that it was an essential pre-requisite to develop ICT skills in the officers involved with agri-extension services to establish a sustainable ICT based knowledge acquisition system in farming community. Preliminary survey revealed that 37 % of 175 officers who underwent training had prior exposure to ICT, whereas only 22% of them used it in extension services. Although 26% had an exposure to the internet, less than 10% used it for knowledge acquisition. Farming community had no prior knowledge in ICT. A programme was developed by OUSL to train 175 officers involved in agri-extension service in the Export Agriculture Department along with some farmers from th...
Plant exposure to high levels of NaCl results in osmotic stress and creates ion toxicity mainly d... more Plant exposure to high levels of NaCl results in osmotic stress and creates ion toxicity mainly due to Cl and, in particular, Na accumulation. In addition, salt stress impacts on nutritional homeostasis of minerals such as, Ca and K. The large detrimental effects of salinity on agriculture require understanding of the underlying genes and mechanisms to improve crop tolerance. A large number of potentially important genes has been identified using forward and reverse genetics, yeast complementation and transcriptomics approaches. The present review gives an overview of membrane transporters that have been assigned functions in uptake, efflux, compartmentation and translocation of Na and Cl. Subsequently, the review critically evaluates how specific genes were identified and assesses whether these would provide valuable targets to improve plant tolerance. _____________________________________________________________________________________________________________
... Plant Physiol, 118: 1455–1461. DeYulia GJ, CĂ¡rcamo Oriana BĂ³rquez-Ojeda JM, Shelton CC, Golde... more ... Plant Physiol, 118: 1455–1461. DeYulia GJ, CĂ¡rcamo Oriana BĂ³rquez-Ojeda JM, Shelton CC, Golde D W. 2005. ... In: Nguyen VN, Duffy R. Proceedings of FAO Rice Conference 2004. Los Banos,Laguna, Philippines: International Rice Research Institute. Lee TM, Lin Y H. 1995. ...
ABSTRACT Rice shows differential tolerance to salinity. However, most of the cultivated varieties... more ABSTRACT Rice shows differential tolerance to salinity. However, most of the cultivated varieties are sensitive to moderate salinity at 3 dS m-1, particularly at their seedling stage. Given the ubiquitous prevalence, wild rice varieties seem to be tolerating wider range of abiotic stresses including high salinity than their cultivated counterparts. The objective of this study was to examine the salt tolerant mechanisms at the seedling stage of wild rice relatives; Oryza nivara L. and Oryza rufipogon L. in comparison to two Oryza sativa L. cultivars with contrasting tolerance to salt stress; tolerant – pokkali and sensitive - IR29. A comparative study was carried out on relative growth rate (RGR), chlorophyll content, relative water content, membrane stability index (MSI), rate of transpiration, monovalent cation content and root anatomy in seedlings of 10 days after sowing (DAS) in response to 100mM NaCl treatment in hydroponic culture system for 12 days. This study showed that in most physiological and growth parameters, O. rufipogon showed salt-responsive trends similar to that observed in the salt tolerant Pokkali. O. rufipogon maintained significantly higher RGR in all tissues in comparison to all varieties except for the root in which RGR was lower than pokkali root. O. rufipogon showed higher plant height, relative water content and membrane stability index under salt treatment than IR29 and O. nivara. Moreover, O. rufipogon maintained a physiologically conducive inplanta [Na+] and [K+] in response to 100 mM NaCl. A unique pattern of short term rapid inplanta Na+ and K+ accumulation within the first 250 min followed by a subsequent decline was observed in O. rufipogon. Despite being had unaffected MSI, O. nivara was as salt sensitive as IR29. Further, O. nivara showed retarded growth and higher inplanta [Na+] content providing evidence for more restrictive occurrence of it against O. rufipogon. The notable characteristic observed in the root anatomy was the elongation of endodermal cells in response to salt stress in all cultivars. This study, based on the comparative analysis of growth, physiological and anatomical parameters identified different salt tolerance mechanisms in wild rice relatives. Thus identified phenotypic mechanisms may lead to discover underlying genes involved to improve salt tolerance in cultivated rice.
Recent advances in next generation sequencing have created opportunities to directly identify gen... more Recent advances in next generation sequencing have created opportunities to directly identify genetic loci and candidate genes for abiotic stress responses in plants. With the objective of identifying candidate genes within the previously identified QTL-hotspots, the whole genomes of two divergent cultivars for salt responses, namely At 354 and Bg 352, were re-sequenced using Illumina Hiseq 2500 100PE platform and mapped to Nipponbare and R498 genomes. The sequencing results revealed approximately 2.4 million SNPs and 0.2 million InDels with reference to Nipponbare while 1.3 million and 0.07 million with reference to R498 in two parents. In total, 32,914 genes were reported across all rice chromosomes of this study. Gene mining within QTL hotspots revealed 1236 genes, out of which 106 genes were related to abiotic stress. In addition, 27 abiotic stress-related genes were identified in non-QTL regions. Altogether, 32 genes were identified as potential genes containing polymorphic non...
Traditionally majority of the rural farming community in Sri Lanka rely on agriculture extension ... more Traditionally majority of the rural farming community in Sri Lanka rely on agriculture extension officers for advice, guidance and training opportunities on crop cultivation, particularly due to government assistance schemes in agriculture. Ongoing COL-L3F project implemented by the Open University of Sri Lanka (OUSL) recognized that it was an essential pre-requisite to develop ICT skills in the officers involved with agri-extension services to establish a sustainable ICT based knowledge acquisition system in farming community. Preliminary survey revealed that 37 % of 175 officers who underwent training had prior exposure to ICT, whereas only 22% of them used it in extension services. Although 26% had an exposure to the internet, less than 10% used it for knowledge acquisition. Farming community had no prior knowledge in ICT. A programme was developed by OUSL to train 175 officers involved in agri-extension service in the Export Agriculture Department along with some farmers from th...
Plant exposure to high levels of NaCl results in osmotic stress and creates ion toxicity mainly d... more Plant exposure to high levels of NaCl results in osmotic stress and creates ion toxicity mainly due to Cl and, in particular, Na accumulation. In addition, salt stress impacts on nutritional homeostasis of minerals such as, Ca and K. The large detrimental effects of salinity on agriculture require understanding of the underlying genes and mechanisms to improve crop tolerance. A large number of potentially important genes has been identified using forward and reverse genetics, yeast complementation and transcriptomics approaches. The present review gives an overview of membrane transporters that have been assigned functions in uptake, efflux, compartmentation and translocation of Na and Cl. Subsequently, the review critically evaluates how specific genes were identified and assesses whether these would provide valuable targets to improve plant tolerance. _____________________________________________________________________________________________________________
... Plant Physiol, 118: 1455–1461. DeYulia GJ, CĂ¡rcamo Oriana BĂ³rquez-Ojeda JM, Shelton CC, Golde... more ... Plant Physiol, 118: 1455–1461. DeYulia GJ, CĂ¡rcamo Oriana BĂ³rquez-Ojeda JM, Shelton CC, Golde D W. 2005. ... In: Nguyen VN, Duffy R. Proceedings of FAO Rice Conference 2004. Los Banos,Laguna, Philippines: International Rice Research Institute. Lee TM, Lin Y H. 1995. ...
ABSTRACT Rice shows differential tolerance to salinity. However, most of the cultivated varieties... more ABSTRACT Rice shows differential tolerance to salinity. However, most of the cultivated varieties are sensitive to moderate salinity at 3 dS m-1, particularly at their seedling stage. Given the ubiquitous prevalence, wild rice varieties seem to be tolerating wider range of abiotic stresses including high salinity than their cultivated counterparts. The objective of this study was to examine the salt tolerant mechanisms at the seedling stage of wild rice relatives; Oryza nivara L. and Oryza rufipogon L. in comparison to two Oryza sativa L. cultivars with contrasting tolerance to salt stress; tolerant – pokkali and sensitive - IR29. A comparative study was carried out on relative growth rate (RGR), chlorophyll content, relative water content, membrane stability index (MSI), rate of transpiration, monovalent cation content and root anatomy in seedlings of 10 days after sowing (DAS) in response to 100mM NaCl treatment in hydroponic culture system for 12 days. This study showed that in most physiological and growth parameters, O. rufipogon showed salt-responsive trends similar to that observed in the salt tolerant Pokkali. O. rufipogon maintained significantly higher RGR in all tissues in comparison to all varieties except for the root in which RGR was lower than pokkali root. O. rufipogon showed higher plant height, relative water content and membrane stability index under salt treatment than IR29 and O. nivara. Moreover, O. rufipogon maintained a physiologically conducive inplanta [Na+] and [K+] in response to 100 mM NaCl. A unique pattern of short term rapid inplanta Na+ and K+ accumulation within the first 250 min followed by a subsequent decline was observed in O. rufipogon. Despite being had unaffected MSI, O. nivara was as salt sensitive as IR29. Further, O. nivara showed retarded growth and higher inplanta [Na+] content providing evidence for more restrictive occurrence of it against O. rufipogon. The notable characteristic observed in the root anatomy was the elongation of endodermal cells in response to salt stress in all cultivars. This study, based on the comparative analysis of growth, physiological and anatomical parameters identified different salt tolerance mechanisms in wild rice relatives. Thus identified phenotypic mechanisms may lead to discover underlying genes involved to improve salt tolerance in cultivated rice.
Uploads
Papers by Prasad Senadheera