Identification and mapping of the QTL for aluminum tolerance introgressed from the new source, ORYZA RUFIPOGON Griff., into indica rice (Oryza sativa L.)

Abstract

This study was conducted to identify and map the quantitative trait locus (QTL) controlling Al tolerance in rice using molecular markers. A population of 171 F(6) recombinant inbred lines (RILs) derived from the cross of Oryza sativa (IR64), the Al susceptible parent, and Oryza rufipogon, the Al tolerant parent, was evaluated for Al tolerance using a nutrient solution with and without 40 ppm of active Al(+3). A genetic map, consisting of 151 molecular markers covering 1,755 cM with an average distance of 11.6 cM between loci, was constructed. Nine QTLs were dentified including one for root length under non-stress conditions (CRL), three for root length under Al stress (SRL) and five for relative root length (RRL). O. rufipogon contributed favorable alleles for each of the five QTLs for RRL, which is a primary parameter for Al tolerance, and individually they explained 9.0-24.9% of the phenotypic variation. Epistatic analysis revealed that CRL was conditioned by an epistatic effect, whereas SRL and RRL were controlled by additive effects. Comparative genetic analysis showed that QTLs for RRL, which mapped on chromosomes 1 and 9, appear to be consistent among different rice populations. Interestingly, a major QTL for RRL, which explained 24.9% of the phenotypic variation, was found on chromosome 3 of rice, which is conserved across cereal species. These results indicate the possibilities to use marker-assisted selection and pyramiding QTLs for enhancing Al tolerance in rice. Positional cloning of such QTLs introgressed from O. rufipogon will provide a better understanding of the Al tolerance mechanism in rice and the evolutionary genetics of plant adaptation to acid-soil conditions across cereal species.

AnALMT1Gene Cluster Controlling Aluminum Tolerance at theAlt4Locus of Rye (Secale cerealeL.)

“…Al-tolerance QTL have been identified on rice 3S (Wu et al 2000;Nguyen et al 2003) in a region containing the closest rice homolog of the barley HvMATE citrate transporter gene. Al tolerance from the wild rice species Oryza rufipogon was most closely associated with markers CDO1395 and RG391 located only 0.5 cM apart, and the nearest flanking marker on the upper side (lower side in Figure 6) was located 11.0 cM away (Nguyen et al 2003). The genetic distance between the MATE gene and the position corresponding to Alt4 in rice (Figure 6) is 12.3-13.2 cM (http:/ /rgp.dna.affrc.go.jp/cgi-bin/statusdb/ irgsp-status.cgi).…”

Characterization of novel genic SSR markers in Linum usitatissimum (L.) and their transferability across eleven Linum species

“…This statement supports the number of transferable EST-SSRs to these five species of the genus Linum which might indicate that similar functional sequences are shared with L. usitatissimum to induce chromosome pairing in artificial hybridizations. Examples from tomato (Tanksley and McCouch, 1997), lettuce (Jeuken and Lindhout, 2004) and rice (Nguyen et al 2003) represent successful gene introgressions from wild relatives which is a real option for linseed breeding. The remarkable level of transferability supports previous findings in other plant species (Saha et al 2004;Varshney et al 2005;Pashley et al 2006;Fu and Peterson, 2010).…”

Genetic Improvement of Rice (Oryza sativa) For Salt Tolerance: A Review

“…Efforts to identify QTL associated with tolerance to drought, salt and mineral deficiencies or toxicities (Champoux et al, 1995;Flowers et al, 2000;Gregorio, 2002;Kamoshita et al, 2002;Nguyen et al, 2002;Price et al, 2002) in a number of genetic backgrounds represent an important first step towards achieving this goal. Additional studies have specifically addressed the problems associated with G x G and G x E (Hittalmani et al, 1995;Zheng et al, 2000;Hittalmani et al, 2003;Li et al, 2003).…”