Studies on Embryogenic Competence and Regeneration Potential With Relation to Anthocyanin Biosynthesis in Cotton (<i>G.hirsutum</i>)

Abstract

Varietal genotype is very important in determining which varieties of cotton will produce embryos because most of the commercial varieties are recalcitrant to regeneration. Identification of genes involved in the induction of competence for embryogenesis and subsequent embryo development presents a challenge for modern molecular biology. Certain varieties of cotton, especially Coker 310 exhibit anthocyanin pigmentation during embryogenic calli induction and form somatic embryos readily, while other genotypes MCU 12 and KC3 does not exhibit anthocyanin pigmentation and are recalcitrant to regeneration. To find out the relationship between anthocyanin synthesis and somatic embryogenesis if any, candidate genes for anthocyanin synthesis and somatic embryogenesis were tested for its presence through PCR analysis in genomic DNA samples of Coker 310, MCU 12 and KC3. The results of this study revealed that the candidate gene sequences for the enzymes involved in anthocyanin biosynthesis (chalcone synthase, flavanone 3 hydroxylase, dihydroflavanol reductase, leucoanthocyanidin deoxygenase and anthocyanidin synthase) and transcription factors that regulate the expression of anthocyanin biosynthesis genes (bHLH and MYB) and the candidate gene sequences encoding the proteins associated with somatic embryogenesis (the arabinogalactan proteins, lipid transfer proteins and high mobility group proteins) were found in all the samples of Coker 310 while none of them were present in the samples of MCU 12 and KC 3. It may be inferred from this study that apart from the genes associated with somatic embryogenesis, genes associated with anthocyanin biosynthesis and regulation may also be involved in somatic embryogenesis and regeneration in cotton. Also, these genes can be used as reliable markers to screen cotton varieties for their embryogenic potential.