STAY GREEN GENES FRAGMENT HOMOLOGY ANALYSIS OF INDONESIAN SORGHUM

Abstract

Stay-green (SGR) is an essential trait in sorghum associated with grain yield under drought and high-temperature stress conditions. The study sought to analyze the homology of the stay-green gene fragment in Indonesian sorghum cultivars, comparing it with the SGR gene sequences in the GenBank database. Two primer pairs, designated as SGR_1 and SGR_2, got designed from the SGR gene of Sorghum bicolor and used to amplify seven sorghum genotypes. The DNA fragments of 300 bp and 1000 bp produced by SGR_1 and SGR_2, respectively, underwent sequencing. Amino acid analysis of the seven sorghum genotypes resulted in high homology with senescence-inducible chloroplast SGR-protein 1 from Zea mays and SGR-chloroplastic of Setaria italica. An observation on a conservative region with the SGR domain noticed SGR genes, derived from sorghum genotypes, clustered separately with those from other SGR genes available in the GenBank database. The first group consisted of a sorghum genotype (Samurai 2), the second group consisted of Super 2, Numbu, and Kawali, while the third group consisted of PI-150-20-A, Pahat, and B69 with coefficient similarity of 10%, 14%, and 30%, respectively. Although Indonesian sorghum has a different group in GenBank, it has similar nucleotide and amino acid sequences, with identity values of 95%-100% and 51%-100%, respectively. The amino acid diversity of the DNA fragments of the SGR gene is highly potential to develop molecular markers, especially the stay green character. The finding will support a sorghum breeding efficiently and precisely, especially for yield improvement under drought-stress conditions.