Nomenclature for HKT transporters, key determinants of plant salinity tolerance.
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Adaptation, Physiological↗
Biomedical subjects
Hong-Xuan Lin
Publications and source records attributed to Hong-Xuan Lin.
[Construction of chromosome segment substitution lines carrying overlapping chromosome segments of the whole wild rice genome and identification of quantitative trait loci for rice quality].
Rice is one of the major staple cereal grains. Most of the important traits of crops are complex traits controlled by quantitative trait loci (QTL). Detection and genetic identification of QTLs can provide insights into molecular and biological mechanisms of development and physiology. Chromosome segment substitution lines (CSSLs) have been proposed as a simple and powerful way to identify QTLs. The demand for rice grain quality becomes increasingly important. The primary components of rice grain quality include appearance, milling and physico-chemical, cooking and eating quality. Most of these traits are complex and controlled by QTLs, so genetic characterization of these traits is more difficult than that of traits each controlled by a singular gene such as Waxy, which controls glutinousness of rice grain. We constructed 133 chromosome segment substitution lines (CSSLs) from backcross progenies (BC3F2) derived from a cross between Teqing (an O. sativa L. ssp. indica variety) as the recurrent parent and wild rice (O. rufipogon Griff.) as the donor parent. In this process, we carried out marker-assisted selection (MAS) by using 118 CAPS or SSR markers covering the whole rice genome (Figs.1, 2). Because phenotypic values of quality trait were significantly different between cultivar Teqing and wild rice, the CSSLs were used to identify QTLs for rice quality traits. Three appearance quality traits (head rice percentage, HRP; percentage of chalky rice grains, PCRG; transparency, TP) and five physico-chemical properties (gelatinization temperature, GT; gel consistency, GC; amylose content, AC; protein content, PC; fat content, FC) were scored using 133 CSSLs which substituted segments covering the whole genome of wild rice. A total of 15 QTLs for five of the eight traits mentioned above (HRP, PCRG, TP, PC and FC) were identified on nine chromosomes, and several QTLs affecting different quality traits were mapped in the same regions (Fig.3, Table 1).
Chromosomes, Plant↗
Simple sequence repeat-based consensus linkage map of Bombyx mori.
We established a genetic linkage map employing 518 simple sequence repeat (SSR, or microsatellite) markers for Bombyx mori (silkworm), the economically and culturally important lepidopteran insect, as part of an international genomics program. A survey of six representative silkworm strains using 2,500 (CA)n- and (CT)n-based SSR markers revealed 17-24% polymorphism, indicating a high degree of homozygosity resulting from a long history of inbreeding. Twenty-nine SSR linkage groups were established in well characterized Dazao and C108 strains based on genotyping of 189 backcross progeny derived from an F(1) male mated with a C108 female. The clustering was further focused to 28 groups by genotyping 22 backcross progeny derived from an F(1) female mated with a C108 male. This set of SSR linkage groups was further assigned to the 28 chromosomes (established linkage groups) of silkworm aided by visible mutations and cleaved amplified polymorphic sequence markers developed from previously mapped genes, cDNA sequences, and cloned random amplified polymorphic DNAs. By integrating a visible mutation p (plain, larval marking) and 29 well conserved genes of insects onto this SSR-based linkage map, a second generation consensus silkworm genetic map with a range of 7-40 markers per linkage group and a total map length of approximately 3431.9 cM was constructed and its high efficiency for genotyping and potential application for synteny studies of Lepidoptera and other insects was demonstrated.
Animals↗
A rice quantitative trait locus for salt tolerance encodes a sodium transporter.
Many important agronomic traits in crop plants, including stress tolerance, are complex traits controlled by quantitative trait loci (QTLs). Isolation of these QTLs holds great promise to improve world agriculture but is a challenging task. We previously mapped a rice QTL, SKC1, that maintained K(+) homeostasis in the salt-tolerant variety under salt stress, consistent with the earlier finding that K(+) homeostasis is important in salt tolerance. To understand the molecular basis of this QTL, we isolated the SKC1 gene by map-based cloning and found that it encoded a member of HKT-type transporters. SKC1 is preferentially expressed in the parenchyma cells surrounding the xylem vessels. Voltage-clamp analysis showed that SKC1 protein functions as a Na(+)-selective transporter. Physiological analysis suggested that SKC1 is involved in regulating K(+)/Na(+) homeostasis under salt stress, providing a potential tool for improving salt tolerance in crops.
Base Sequence↗