Characterization and gene mapping of a brittle culm mutant of diploid wheat (Triticum monococcum L.) with irregular xylem vessels development

• Published in: Acta physiologiae plantarum Vol. 35; no. 8; pp. 2407 - 2419
• Main Authors: Ansari, Mohammad Javed, Al-Ghamdi, Ahmad, Usmani, Salma, Kumar, Rahul, Nuru, Adgaba, Singh, Kuldeep, Dhaliwal, Harcharan Singh
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-08-2013; Springer Berlin Heidelberg
• Subjects: Agriculture; Biomedical and Life Sciences; biosynthesis; cell walls; cellulose; chromosome mapping; chromosomes; diploidy; flowering; Fourier transform infrared spectroscopy; genes; genomics; leaves; Life Sciences; lodging; microsatellite repeats; molecular cloning; mutants; mutation; Original Paper; parents; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; scanning electron microscopy; screening; Triticum monococcum subsp. aegilopoides; Triticum monococcum subsp. monococcum; vascular bundles; wheat; xylem vessels; Irregular xylem vessels; L.; mutant; Gene mapping; SSR marker; Cellulose
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-013-1275-0

Diploid wheat, Triticum monococcum L. (einkorn) is an ideal plant material for wheat functional genomics. Brittle culm mutant was identified by screening of the ethyl methane sulphonate-treated M ₂ progenies of a T. monococcum accession pau14087 by banding the plant parts manually. The brittle culm mutant with drooping leaves, early flowering, reduced tiller numbers and susceptible to lodging had also exhibited brittleness in all plant parts than the wild-type parents. Comprehensive mechanical strength, histological, biochemical, scanning electron microscopy, and Fourier transform infrared spectroscopy analyses of brittle culm mutant supplemented and complemented the findings that the mutant had defective cellulose biosynthesis pathway and deposition of cell wall materials on secondary cell wall of mechanical tissues. Microscopic studies demonstrated that the decrease in cellulose contents resulted in the irregular cell wall organization in xylem vessels of leaf vascular bundles. To map the brc5 mutant, mapping populations were developed by crossing the brittle culm mutant with wild Triticum boeoticum acc. pau5088, having non-brittle characters. The brittle culm mutation was mapped between SSR markers, Xcfd39 and Xgwm126 on 5AᵐL chromosome of T. monococcum, with genetic distances of 2.6 and 4.8 cM, respectively. The brc5 mutant mapped on 5AᵐL, being distinct from a previously mapped brittle culm mutant in wheat, has been designated as brc5. The work on fine mapping and map-based cloning of brc5 gene regulating synthesis and deposition of cellulose on the secondary cell wall is in progress.