Comparative Genomics and Gene Expression Analysis for Yield and Quality Traits in Garlic

Abstract

Garlic (Allium sativum) is the second most widely cultivated Allium species grown in the world. The production of Pakistani garlic varieties is hampered by a number of factors. Among them scarcity of genetic data and functional characterization of the genes involved in garlic quality are the major constraints for improvement in breeding programmes. Analyzing the diversity of key gene families involved in plant architecture and adaptation among five different local and exotic garlic cultivars was attempted in this study. For this purpose, four cultivars namely “Local Red, NARC G1, China White and an Advance line” were selected. The Allium genome search revealed 12 key genes involved in yield and quality parameters like flavour, sulphur metabolism, bulbing and colour of the clove. Out of these 4 genes, Ft-Like (FT), Anthocyanidin Synthase (ANS), Lachrymatory Factor Synthase (LFS) and Sulphite Reductase (SIR) were selected for phylogenetic and gene expression studies. Homologous sequences of these genes were retrieved from the NCBI and Ensembl plants databases. Phylogenetic trees of FT, ANS, LFS and SIR form different plant species exhibited clustering into their corresponding clades. Realtime-RT-PCR analysis confirmed the expression of these yield related genes in both the bulb and leaves of five different cultivars of garlic (Allium sativum). The expression of these yield and quality related genes was stronger in China white as compared to other varieties. FT gene exhibited strong expression in Local red bulb. FSR gene was least expressed in the Local Red but moderately expressed in China White. SIR was strongly expressed in both bulb and leaf tissue of all the varieties under study. Morphological analysis was also carried out to compare the yield potential in different cultivars. From the mean value analysis and LSD values, “China white” variety performed better with regard to Plant Height, Stem Diameter, Flag Leaf Length, Flag Leaf width, Smaller Leaf length, Smaller Leaf width, No of cloves and 100 clove weight.