Browsing by Author "Batlang, Utlwang"

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    Coordinated regulation of photosynthesis in rice increases yield and tolerance to environmental stress
    Ambavaram, Madana M. R.; Basu, Supratim; Krishnan, Arjun; Ramegowda, X.; Batlang, Utlwang; Rahman, L.; Baisakh, Niranjan; Pereira, Andy (Nature Publishing Group, 2014-12-01)
    Improving photosynthetic efficiency to increase crop yield is an important goal of plant breeders. Here, Ambavaram et al. identify a transcription factor that is a key regulator of photosynthetic carbon metabolism in rice and show that its overexpression enhances grain yield.
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    Identification of Drought-Responsive Genes and Validation for Drought Resistance in Rice
    Batlang, Utlwang (Virginia Tech, 2010-01-05)
    Drought stress was studied in rice (Oryza sativa) and maize (Zea mays) to identify drought-responsive genes and associated biological processes. One experiment with rice examined drought responses in vegetative and reproductive tissues and identified drought-responsive genes in each tissue type. The results showed that brief periods of acute drought stress at or near anthesis reduced photosynthetic efficiency and ultimately lowered grain yield. Yield was reduced as a result both of fewer spikelets developed and of lower spikelet fertility. Affymetrix arrays were used to analyze global gene expression in the transcriptomes of rice vegetative and reproductive tissue. Comparative analysis of the expressed genes indicated that the vegetative and reproductive tissues responded differently to drought stress. An experiment was conducted with maize, using GS-FLX pyrosequencing to identify differentially expressed genes in vegetative and reproductive tissues; and these results were compared with those from the just-described rice transcriptome. Some of the drought-responsive genes in the maize reproductive tissue were validated by quantitative real time polymerase chain reaction (qRT-PCR). The differentially expressed genes common to both maize and rice were further analyzed by gene ontology analysis to reveal core biological processes involved in drought responses. In both species, drought caused a transition from protein synthesis to degradation, and photosynthesis was one of the most severely affected metabolic pathways. In a validating experiment, a drought-responsive transcription factor found in rice and dubbed HIGHER YIELD RICE (HYR) was constitutively expressed in rice, and the transgenic HYR plants were studied. Under well-watered conditions, the HYR plants developed higher rates of photosynthesis, greater levels of soluble sugars (glucose, fructose, and sucrose), more biomass, and higher yield. They also exhibited a drought-resistant phenotype, with higher water use efficiency, photosynthesis, and relative leaf water content under drought stress. Taken together, these studies demonstrate the potential value of newer technologies for identifying genes that might impart drought resistance and for using such genes to make crops more productive either in the presence or in the absence of drought stress.
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    Studies With Triazoles to Alleviate Drought Stress in GreenHouse-Grown Maize (Zea mays) Seedlings
    Batlang, Utlwang (Virginia Tech, 2006-05-05)
    In semi-arid environments, dry-land farming often exposes crops to drought stress. Although some plant species are well adapted to drought, most crops are not. Drought can reduce plant populations and limit growth and development in ways that have serious yield consequences. Planting at the beginning of the wet season, when rainfalls are often sporadic and unreliable, can expose young maize seedlings to severe drought. Through the use of plant growth regulators (PGR), maize seedlings can perhaps be altered to elicit responses that mimic drought adaptation mechanisms. A series of studies conducted in the laboratory and greenhouse looked at the response of maize seedlings (two hybrids that differed in their reported drought sensitivity) to severe drought and to PGR applications with or without drought. Results showed that drought stress altered plant morphology and key physiological parameters. Applications of three triazoles (paclobutrazol, uniconazole and tetraconazole) altered morphology and physiology in ways that might impart drought resistance. Paclobutrazol and uniconazole increased root:shoot ratio in laboratory studies and in the greenhouse. When compared to non-triazole-treated controls, uniconazole and paclobutrazol treatments caused water conservation in earlier stages of drought stress, and therefore afforded increased transpiration (and presumably less stress) at later stages. Uniconazole and tetraconazole increased photosynthesis of well-watered plants. Proline content was increased to a greater degree by these same two triazoles under drought stress conditions. It is hoped that knowledge obtained from these studies can be extended to drought-prone areas where maize dry-land farming is practiced.