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ARS Home » Midwest Area » Columbus, Ohio » Soil Drainage Research » Research » Publications at this Location » Publication #133456
Title: IMPROVING PLANT'S TOLERANCE TO WATER STRESS BY MOLECULAR PLANT BREEDING AND GENETIC TRANSFORMATION

Author
item Vantoai, Tara

Submitted to: Conference of the International Society for Plant Anaerobiosis
Publication Type: Proceedings
Publication Acceptance Date: 4/4/2001
Publication Date: 6/12/2001
Citation: Vantoai, T.T. 2001. Improving plant's tolerance to water stress by molecular plant breeding and genetic transformation. Conference of the International Society for Plant Anaerobiosis.

Interpretive Summary:

Technical Abstract: Soil flooding affects plant growth and productivity. Flooding causes premature sensecence: leaf chlorosis, necrosis, defoliation, cessation of growth and reduced yield. This study was conducted to identify quantitative trait loci (QTL) associated with tolerance of soybean to soil waterlogging. Two recombinant inbred (RI) populations were subjected to two weeks of waterlogging at the early flowering stage. We identified a single QTL, linked to marker Sat_064, associated with improved plant growth (from 11 to 18%) and grain yields (from 47 to 180%) in waterlogged environments. This highly significant QTL was identified in both RI populations and in both 1997 and 1998 environments. The Sat_64 QTL was uniquely associated with waterlogging tolerance and was not associated with maturity, plant height or grain yield. Near isogenic lines with and without the Sat_64 marker have been developed and are being field tested to confirm the association of the QTL with the tolerance of soybean to waterlogging stress. To determine the effects of autoregulated cytokinin production on flooding tolerance, a chimeric gene containing the senescence-specific SAG12 promoter and the ipt gene coding for cytokinin biosynthesis was constructed and introduced into Arabidopsis plants. The transgenic lines appeared healthy and normal, but were consistently more tolerant to complete submergence, waterlogging and drought than wild-type plants, and after one week of stress, the SAG12: ipt plants contained 3 to 10-fold more cytokinin. This study provides a novel technique to develop stress-tolerant crops and the means to identify the cytokinin-regulated gene expression pathways associated with the stress tolerance responses.