Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 1/12/2002
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Aluminum (Al) toxicity is a major soil factor that limits crop productivity on the earth's acidic soils. Al toxicity is primarily associated with damage to the root system, which in turn leads to susceptibility to other abiotic stresses. In many crops, significant natural variation for Al tolerance exists, and this has been successfully mined by plant breeders to odevelop more Al-tolerant varieties. In bread wheat, major genes are presen that confer high levels of Al tolerance, and studies have established that genetic variation for Al tolerance in bread wheat is mechanistically associated with Al-inducible malate release from the root tip. Efforts to isolate the major wheat Al tolerance gene located on chromosome arm 4DL are now being undertaken. The research employs chromosome deletion lines of wheat as a crude gene knockout system. A set of these lines representing chromosome arm 4DL was used to physically map the Al tolerance gene on this sarm. Sister deletion lines differing for the presence vs. absence of this Al tolerance gene are now being used to recover candidate Al tolerance genes. The research strategy centers around the fact that by eliminating the Al tolerance gene, its transcript will also be eliminated. Thus, comparative analysis of RNA from root tips of the sister deletion lines was used to identify genes differentially expressed in their root tips, and located on the chromosome segment harboring the Al tolerance gene. Progress on the recovery, characterization, and validation of these candidate Al tolerance genes will be presented. The isolation of Al tolerance genes is expected to provide options for genetic engineering of this trait in crops where natural variation is not sufficient to permit development of more Al- tolerant varieties by traditional methods.