Genetic and molecular analysis of seed coats and pollen grains of Phaseolus vulgaris L. during their developmental stages

Abstract

Phaseolus vulgaris L. (Common bean) is a valuable and highly nutritious food legume and exhibits a wide variety of seed coat patterns and colors that controlled by a group of specific genes who regulate the flavonol and anthocyanin biosynthetic pathways which in turn responsible for appearing the seed coat colours. This attracted the attention of the current study to select seeds of three varieties of P. vulgaris var. strike, contender, and wonder which had different seed coats colours (creamy, Brown to deep brown, and Reddish spotty (pinto) beans respectively). The study assessed the phenotypic characteristics of the seeds and seed coats based on seed germination and seedling growth parameters from one hand and macro, micro-phenotypic aspects of seed coat using stereomicroscope and scanning electron microscope (SEM) from other hand. The current study concluded that all markers used in present study from phenotypic to DNA-based molecular markers differ in their resolving power to detect genetic variations, identification, genetic structure, and type of data they generate for each species. Each technique has its own advantages and limitations. Phenotypical and protein-based markers are dependent on the gene expression of DNA at exons (coding) region only and may be influenced by environmental conditions, tissue specificity, developmental stages and age. On the other hand, the DNA-based markers are dependent on coding (exons) and non-coding (intron) regions and are not governed by above external factors because any changes in them are due to natural mutation within the gene sequence during replication that, in turn, may be repaired. Thus, the DNA-based markers seemed to be the best-suited molecular assay for fingerprinting and assessing genetic structure of each one of P. vulgaris L. variety with high accuracy by which the conservation of the studied plant can be made easy. The current study showed also that P. vulgaris var . contender with brown to deep brown seed coat color were more pronounced than the other two varieties in most analyses used in this study.