Wild Crop Relatives: Genomic and Breeding Resources

Many plants contain carbohydrate-binding proteins that are commonly designated as lectins, agglutinins, or hemagglutinins. Due to the obvious differences in molecular structure, biochemical properties, and carbohydrate-binding specificity, plant lectins are usually considered a complex and heterogeneous group of proteins. Recent advances in the structural analysis of lectins and molecular cloning of lectin genes enable subdividision of plant lectins in a limited number of subgroups of structurally and evolutionary related proteins. Four major lectin families, namely, the legume lectins, the chitin-binding lectins composed of hevein domains, the type 2 ribosome-inactivating proteins, and the monocot mannose-binding lectins comprise the majority of all currently known plant lectins. In addition to these four large families the jacalin-related lectins, the amaranthin family, and the Cucurbitaceae phloem lectins are now recognized as separate subgroups. Each of the above-mentioned lectin families is discussed...

Plant Lectins: A Composite of Several Distinct Families of Structurally and Evolutionary Related Proteins with Diverse Biological Roles

Plant toxic proteins with insecticidal properties. A review on their potentialities as bioinsecticides

Chromosomal regions associated with marker segregation distortion in rice were compared based on six molecular linkage maps Mapping populations were derived from one interspecific backcross and five inter-subspecific (indica/japonica) crosses, including two F2 populations, two doubled haploid (DH) populations, and one recombinant inbred (RI) population Mapping data for each population consisted of 129-629 markers Segregation distortion was determined based on chi-square analysis (P < 001) and was observed at 68-318%, of the mapped marker loci Marker loci associated with skewed allele frequencies were distributed on all 12 chromosomes Distortion in eight chromosomal regions bracketed previously identified gametophyte (ga) or sterility genes (S) Distortion in three other chromosomal regions was found only in DH populations, where japonica alleles were over-represented, suggesting that loci in these regions may be associated with preferential regeneration of japonica genotypes during anther culture Three additional clusters of skewed markers were observed in more than one population in regions where no gametophytic or sterility loci have previously been reported A total of 17 segregation distortion loci may be postulated based on this study and their locations in the rice genome were estimated

Chromosomal regions associated with segregation distortion of molecular markers in F2 , backcross, doubled haploid, and recombinant inbred populations in rice (Oryza sativa L.)

[...] The purpose of this paper is to describe available marker types and examine factors critical for their use in map construction and MAS [marker-assisted selection]. This review clarifies how genetic markers are used in map construction and defines the potential use of genetic maps for MAS [...]

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Genetic Markers, Map Construction, and Their Application in Plant Breeding

A restriction fragment length polymorphism (RFLP)-based linkage map for common bean (Phaseolus vulgaris L.) covering 827 centiMorgans (cM) was developed based on a F2 mapping population derived from a cross between BAT93 and Jalo EEP558. The parental genotypes were chosen because they exhibited differences in evolutionary origin, allozymes, phaseolin type, and for several agronomic traits. The segregation of 152 markers was analyzed, including 115 RFLP loci, 7 isozyme loci, 8 random amplified polymorphic DNA (RAPD) marker loci, and 19 loci corresponding to 15 clones of known genes, 1 virus resistance gene, 1 flower color gene, and 1 seed color pattern gene. Using MAPMAKER and LINKAGE-1, we were able to assign 143 markers to 15 linkage groups, whereas 9 markers remained unassigned. The average interval between markers was 6.5 cM; only one interval was larger than 30 cM. A small fraction (9%) of the markers deviated significantly from the expected Mendelian ratios (1∶2∶1 or 3∶1) and mapped into four clusters. Probes of known genes belonged to three categories: seed proteins, pathogen response genes, and Rhizobium response genes. Within each category, sequences homologous to the various probes were unlinked. The I gene for bean common mosaic virus resistance is the first disease resistance gene to be located on the common bean genetic linkage map.

S. M. Tsail

Papers

Towards an integrated linkage map of common bean 2. Development of an RFLP-based linkage map