Identification and Characterization of Badh2 Gene in Mutant Basmati Rice

Abstract

Oryza sativa L., commonly known as rice, is a monocotyledonous plant belonging to the Plantae kingdom. It falls under the genus Oryza, and "sativa" refers to the species of rice. Rice has a relatively small genome size of 430 Mbp, making it an attractive choice for experimental purposes. It is the third largest crop worldwide and serves as a staple food for approximately half of the global population. Aroma in basmati rice is a distinct trait found in the grains of rice in Asia and Africa. This aroma is associated with genetic mutations that occurred during the evolution of rice. Different combinations of genes linked to aroma traits give rise to various flavors in aromatic genotypes originating from different regions. The fragrance trait in basmati rice is controlled by six chromosomes (4, 5, 8, 9, 11, and 12). Specific genes, such as fgr and badh2 (recessive), as well as BAD2 and RG28 (dominant), have been identified as playing a role in regulating this unique trait. The aroma in basmati rice is created due to the presence of Betaine aldehyde dehydrogenase, specifically Betaine-aldehyde-dehydrogenase-2 (Badh2), which is crucial for the accumulation of the fragrant compound 2-acetyl-1-pyrroline (2AP) in rice. Inactivation of Badh2 caused by an 8bp nucleotide deletion in exon 7 leads to an increase in the level of 2AP. The main objective of this research was to identify different basmati and non-basmati rice plants from an EMS mutagenized rice population. Gene-specific primers for the badh2 gene were used to confirm whether the EMS mutants belonged to the basmati or non-basmati varieties with gene of badh2.