Badh2 Gene Research Articles

Enhancing rice aroma through innovative approaches

Aromatic rice is used extensively in many different cuisines around the world for its wonderful aroma and cooking qualities. Aromatic rice varieties such as Basmati and non-Basmati fragrant rice have gained popularity in both domestic and foreign markets, despite their origins being predominantly in Southeast Asia and the Indian subcontinent. The primary gene responsible for rice aroma is the fgr/Badh2/Os2-AP, situated on chromosome 8 and encodes betaine aldehyde dehydrogenase 2 (Badh2). Key aroma compounds are attributed to over 500 volatiles. The primary aromatic molecule in rice, 2-acetyl-1-pyrroline (2-AP), accumulates as a result of mutations in this gene and gives rice its distinctive scent. Aroma is not decided by single compound rather it is decided by volatile profile and also by environmental factors. The identification of Quantitative Trait Loci (QTLs) linked to fragrance features on different chromosomes has improved our comprehension of the genetic processes behind rice scent. Advances in genetic engineering, particularly CRISPR/Cas9 and TALEN have facilitated the manipulation of the Badh2 gene, enhancing aroma profiles in rice. Additionally, gene silencing and introgression techniques have also proven in increasing 2-AP content. The review explores the biochemical properties and advancement of aromatic rice, emphasizing its complex inheritance patterns and potential for breeding improvement.

Metabolome and Transcriptome Unveil the Correlated Metabolites and Transcripts with 2-acetyl-1-pyrroline in Fragrant Rice.

Fragrance is a valuable trait in rice varieties, with its aroma significantly influencing consumer preference. In this study, we conducted comprehensive metabolome and transcriptome analyses to elucidate the genetic and biochemical basis of fragrance in the Shangsixiangnuo (SSXN) variety, a fragrant indica rice cultivated in Guangxi, China. Through sensory evaluation and genetic analysis, we confirmed SSXN as strongly fragrant, with an 806 bp deletion in the BADH2 gene associated with fragrance production. In the metabolome analysis, a total of 238, 233, 105 and 60 metabolic compounds exhibited significant changes at the seedling (S), reproductive (R), filling (F), and maturation (M) stages, respectively. We identified four compounds that exhibited significant changes in SSXN across all four development stages. Our analyses revealed a significant upregulation of 2-acetyl-1-pyrroline (2AP), the well-studied aromatic compound, in SSXN compared to the non-fragrant variety. Additionally, correlation analysis identified several metabolites strongly associated with 2AP, including ethanone, 1-(1H-pyrrol-2-yl)-, 1H-pyrrole, and pyrrole. Furthermore, Weighted Gene Co-expression Network Analysis (WGCNA) analysis highlighted the magenta and yellow modules as particularly enriched in aroma-related metabolites, providing insights into the complex aromatic compounds underlying the fragrance of rice. In the transcriptome analysis, a total of 5582, 5506, 4965, and 4599 differential expressed genes (DEGs) were identified across the four developmental stages, with a notable enrichment of the common pathway amino sugar and nucleotide sugar metabolism in all stages. In our correlation analysis between metabolome and transcriptome data, the top three connected metabolites, phenol-, 3-amino-, and 2AP, along with ethanone, 1-(1H-pyrrol-2-yl)-, exhibited strong associations with transcripts, highlighting their potential roles in fragrance biosynthesis. Additionally, the downregulated expression of the P4H4 gene, encoding a procollagen-proline dioxygenase that specifically targets proline, in SSXN suggests its involvement in proline metabolism and potentially in aroma formation pathways. Overall, our study provides comprehensive insights into the genetic and biochemical mechanisms underlying fragrance production in rice, laying the foundation for further research aimed at enhancing fragrance quality in rice breeding programs.

Badh2 gene-based DNA hybridization assay for non-fragrant and fragrant Thai rice detection

2-Acetyl-1-pyrroline (2AP) is the major compound mixed in the aroma intensities of fragrant rice cultivars. The recessive gene betaine aldehyde dehydrogenase (badh2) controls the biosynthesis of 2AP in fragrant rice cultivars. However, the 2AP content was also found in non-fragrant rice cultivars based on the environmental factors of the cultivation areas. In this study, we developed a new allele-specific method (sandwich DNA hybridization assay) for the recessive badh2 gene assay to classify the non-fragrant and fragrant of Thai rice cultivars. Moreover, the 2AP content of all rice cultivars was investigated by the GC-MS method to confirm the specific distinction of this assay. The results showed that the 2AP content was determined in all rice cultivars with a range of 4.4 ± 0.06–323.0 ± 4.04 µg/g. The 2AP content of all rice cultivars could be categorized into two groups: the first group with a range of 4.4 ± 0.06–10.3 ± 0.26 µg/g, and the second group with a range of 101.7 ± 2.00–323.0 ± 4.04 µg/g. The DNA hybridization assay results indicated that the first group was comprised of non-fragrant rice cultivars, and the second group was comprised of fragrant rice cultivars. Thus, results further suggested that the newly developed method using a DNA hybridization assay confirmed the 2AP content of the non-fragrant and fragrant rice cultivars with the advantages of accuracy and selectivity. The proposed novel assay also was a suitable method for separating the non-fragrant rice cultivars from the fragrant rice cultivars.

GA3 and BAP phytohormone seed priming enhances germination and PEG induced drought stress tolerance in soybean by triggering the expression of osmolytes, antioxidant enzymes and related genes at the early seedling growth stages

Drought stress strongly affects seed germination and seedling development during the early stages of plant growth in soybean (Glycine max L.). Seed priming with phytohormone (PH) is known to regulate various physiological and biochemical processes that govern plant growth and yield under optimal and stress conditions. In the present study, the effects of seed priming with Gibberellic acid (GA3) (0.28 mM), 6-Benzyl aminopurine (BAP) (20 mM) and Methyl Jasmonate (MJ) (2.5 mM) was studied during germination and at early seedling growth stages in JS-335 (drought sensitive) and MAUS-71 (moderately drought tolerant) soybean varieties under PFG induced drought stress conditions. The seed priming effects were studied in terms of germination percentage and rate (Timson Index), accumulation of osmolytes (proline and glycine betaine), antioxidant enzymes activity (superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT)), and the relative expression of genes viz., Cu/Zn-superoxide dismutase copper chaperone (SOD-CCS) , iron-superoxide dismutase (SODB2) , betaine aldehyde dehydrogenase (BADH2) and dehydration-responsive element binding protein (DREB2A). The germination percentage of non-primed soybean seeds decreased under drought stress but significantly increased upon GA3 and BAP priming. Interestingly, seed priming with MJ completely inhibited the germination in both the varieties. GA3 and BAP seed priming increased proline and glycine betaine accumulation under PEG induced drought stress in both the soybean varieties. The results showed that the activities of SOD, APX and CAT were significantly enhanced in the leaves of seedlings raised from GA3 and BAP-primed seeds, as compared to the non-primed seeds under the drought stress conditions. Isozyme profiling of SOD and APX revealed that the GA3 and BAP seed priming treatments enhanced the drought-inducible expression of SOD isozymes rather than inducing novel isoforms. In case of APX isozymes, GA3 seed priming appears to preserve APX isozyme diversity in both varieties, and BAP seed priming elevated the expression of APX isoforms in both soybean varieties under the drought conditions. In response to the drought stress, relative expression of the genes associated with superoxide dismutase and glycine betaine viz., SOD CCS, SODB2, BADH2 and DREB2A was markedly upregulated in the leaves of seedlings raised from the GA3 and BAP primed seeds in both the soybean varieties. The global correlation analysis designated that the osmolyte Proline, antioxidant enzyme APX and CAT, and SOD CCS, SODB2, BADH2 and DREB2A genes were potent regulator for drought stress tolerance mechanism in soybean. This study illuminates the intricate interplay of GA3 and BAP hormonal seed priming during the germination and early seedling stages in soybean plants under the drought stress. This finding emphasizes the critical consideration of genotype specific reactions to the hormonal seed priming under PEG induced drought stress conditions.

Application of Silicon Influencing Grain Yield and Some Grain Quality Features in Thai Fragrant Rice.

Silicon (Si) is a beneficial nutrient that has been shown to increase rice productivity and grain quality. Fragrant rice occupies the high end of the rice market with prices at twice to more than three times those of non-fragrant rice. Thus, this study evaluated the effects of increasing Si on the yield and quality of fragrant rice. Also measured were the content of proline and the expression of the genes associated with 2AP synthesis and Si transport. The fragrant rice varieties were found to differ markedly in the effect of Si on their quality, as measured by the grain 2AP concentration, while there were only slight differences in their yield response to Si. The varieties with low 2AP when the Si supply is limited are represented by either PTT1 or BNM4 with only slight increases in 2AP when Si was increased. Si affects the gene expression levels of the genes associated with 2AP synthesis, and the accumulation of 2AP in fragrant rice mainly occurred through the upregulation of Badh2, DAO, OAT, ProDH, and P5CS genes. The findings suggest that Si is a potential micronutrient that can be utilized for improving 2AP and grain yield in further aromatic rice breeding programs.

Downregulation of badh2 gene is responsible for aroma in Kon Joha rice (Oryza sativa L.) of Assam

Downregulation of badh2 gene is responsible for aroma in Kon Joha rice (Oryza sativa L.) of Assam

Multiple mutations in BADH2 gene reveal the novel fragrance allele in indica rice (Oryza sativa L.)

Multiple mutations in BADH2 gene reveal the novel fragrance allele in indica rice (Oryza sativa L.)

Effect of high temperature stress on metabolome and aroma in rice grains

Heat stress poses a significant challenge to global rice production, affecting yield and grain quality. Elevated temperatures during the flowering and grain-filling stages, both day and night, lead to reduced yield and compromised grain quality. This impact is more pronounced during nighttime high-temperature stress, seriously threatening rice productivity. With global temperatures rising, there is a looming threat to rice production. Aromatic rice, prized for superior aroma and grain quality, is particularly vulnerable to heat. Therefore, the present work has been carried out to investigate how high temperature affects the aromatic metabolites in rice grains among the 15 rice genotypes (fourteen aromatic and one non-aromatic rice i.e., Nagina 22). Results from the present study indicated that the inactive (mutated) BADH2 gene expression was down-regulated under high-temperature stress conditions and no 2-acetyl-1-pyrroline (2-AP) accumulation was detected in the selected rice genotypes. However, the increase in levels of L-proline (precursor molecule for 2-AP) was detected, and due to the down-regulation of inactive BADH2, the oxidation of L-proline into 2-AP was affected. Proline amino acid significantly increased under high temperatures, impacting aroma quality. Metabolome studies revealed variations in compound detection among scented rice genotypes. Understanding these metabolites aids in addressing the loss of aroma in fragrant rice genotypes, offering insights into developing stable aromatic rice varieties under elevated temperature conditions. The study aims to identify metabolites causing aroma loss in aromatic rice. Results will aid in understanding aroma depletion mechanisms in scented rice under high-temperature stress, guiding the development of a stable aromatic rice variety in elevated temperatures.

Variability in 2-acetyl-1-pyrroline production and associated mutations in BADH2 gene in aromatic rice cultivars of Bangladesh

Aroma is a special trait and aspect of the end-use quality of rice and its principal component is 2-acetyl-1-pyrroline (2AP). Sequence variants of betaine aldehyde dehydrogenase (BADH2) gene on rice chromosome 8 are associated with fragrance, and the most prominent mutation is an 8-bp deletion and three single nucleotide polymorphisms (SNPs) in exon 7. In this study, we analyzed sequence variations in exon 7 of BADH2 in four locally popular aromatic rice cultivars and six non-aromatic high-yielding rice varieties in Bangladesh. Sequencing and alignment analysis revealed that two aromatic rice cultivars, Kataribhog and Sakkorkhana, had an 8-bp deletion (discontinuous) and one SNP (A/T) in exon 7 of the BADH2 gene. However, deletions were absent in the other two aromatic rice cultivars (Chinigura and Ranisalut) and all high-yielding varieties (BRRI dhan28, BRRI dhan29, BRRI dhan86, BRRI dhan87, BRRI dhan92 and BINA dhan10). Gene expression analysis using specific markers also supports these findings. Our results suggest that aromaticity in local rice cultivars in Bangladesh may be regulated by differential genetic mechanisms. Further studies are needed to elucidate the genetic mechanisms and fragrant compound(s) involved in the fragrance traits of Chinigura, Ranisalut, and other locally cultivated aromatic rice varieties that are critical for the development of high-yield aromatic rice by knocking out the targeted gene(s) using CRISPR-Cas genome editing.

The drought-tolerant rhizobacterium, Pseudomonas putida AKMP7, suppresses polyamine accumulation under well-watered conditions and diverts putrescine into GABA under water-stress, in Oryza sativa

Drought-tolerant plant growth promoting rhizobacteria (PGPR) have been reported to alleviate water-stress in plants that they associate with. Here, we report the impact of a free-living, drought-tolerant PGPR strain, Pseudomonas putida AKMP7 on (a) morpho-physiological responses and (b) metabolism of the three major polyamines-namely, putrescine (Put), spermidine (Spd) and spermine (Spm) in well-watered and water-stressed Oryza sativa (BPT5204). The bacterium significantly improved the plant growth and biomass, decreased membrane damage, electrolyte leakage and plant proline levels under water-stress, indicating drought alleviation. Dehydration did not affect the root colonization efficiency of the bacterium. We observed that the concentrations of all three polyamines were downregulated in rice leaves under well-watered conditions by AKMP7 inoculation. Under water-stress, however, AKMP7 caused a significant decrease only in the levels of foliar Spm, while Put and Spd levels did not majorly fluctuate. Transcript levels of most of the polyamine biosynthetic genes studied (AIH involved in Put biosynthesis; SPD/SPM2, SPD/SPM3 and SAMDC2, involved in Spd and Spm biosynthesis) positively correlated with the low polyamine levels in the inoculated plants, vs. the non-inoculated ones under well-watered conditions. While similar trends were observed in the water-stressed, inoculated plants vs. water-stressed, non-inoculated plants, the reduction in only Spm (and not Put and Spd) was a potential consequence of the interplay of both, its biosynthesis and back-conversion. In water-stressed plants, AKMP7 caused a small downregulation in AIH, while stronger downregulations in the expressions of SPD/SPM2 as well as SAMDC2 were seen. Furthermore, the Spd to Put back-conversion gene, PAO3 exhibited a downregulation on AKMP7 treatment under water-stressed conditions. There was also an increase in the expression of BADH2 gene, leading to a concomitant increase in foliar GABA levels in inoculated, water-stressed plants vs. their non-inoculated counterparts. The overall conclusion from this study is- P. putida AKMP7 tightly regulates polyamine homeostasis in rice plants, both under well-watered and water-stressed conditions by lowering polyamine levels, through (a) transcriptional control of polyamine biosynthetic genes under well-watered conditions and (b) a combination of biosynthesis, back-conversion and catabolism of polyamines under water-stress.

CRISPR/Cas9-mediated editing of Wx and BADH2 genes created glutinous and aromatic two-line hybrid rice.

Amylose content (AC) is one of the physicochemical indexes of rice quality, which is largely determined by the Waxy (Wx) gene. Fragrance in rice is favored because it adds good flavor and a faint scent. Loss of function of the BADH2 (FGR) gene promotes the biosynthesis of 2-acetyl-1-pyrroline (2AP), which is the main compound responsible for aroma in rice. Here, we used a CRISPR/Cas9 system to simultaneously knock out Wx and FGR genes in 1892S and M858, which are the parents of an indica two-line hybrid rice, Huiliangyou 858 (HLY858). Four T-DNA-free homozygous mutants (1892Swxfgr-1, 1892Swxfgr-2, M858wxfgr-1, and M858wxfgr-2) were obtained. The 1892Swxfgr and M858wxfgr were crossed to generate double mutant hybrid lines HLY858wxfgr-1 and HLY858wxfgr-2. Size-exclusion chromatography (SEC) data indicated that true AC of the wx mutant starches ranged from 0.22 to 1.63%, much lower than those of the wild types (12.93 to 13.76%). However, the gelatinization temperature (GT) of the wx mutants in backgrounds of 1892S, M858, and HLY858 were still high, and showed no significant differences with the wild type controls. The aroma compounds 2AP content in grains of HLY858wxfgr-1 and HLY858wxfgr-2 were 153.0 μg/kg and 151.0 μg/kg, respectively. In contrast, 2AP was not detected in grains of HLY858. There were no significant differences in major agronomic traits between the mutants and HLY858. This study provides guidelines for cultivation of ideal glutinous and aromatic hybrid rice by gene editing.

A non-synonymous SNP in homolog of BADH2 gene is associated with fresh pod fragrance in dolichos bean (Lablab purpureus var. lignosus (Prain) Kumari).

Fresh pods are harvestable and marketable economic product in dolichos bean. Fresh pod fragrance is one of the 'farmers' and 'consumers' preferred traits in dolichos bean varieties. The pods with high fragrance fetch a premium price in the market. In breeding programmes, pod fragrance is routinely assessed by organoleptic (sensory) means, which is highly relative and subjective. Identification of linked DNA markers not only offer an objective means but also enable selection of fragment genotypes at seedling stage itself. Betaine aldehyde dehydrogenase (BADH) is known to be the key gene responsible for fragrance in other legumes such as vegetable soybean and mung bean. Taking cues from highly conserved domains in proteins coded by BADH genes, we isolated dolichos bean homolog (LpBADH2) of soybean GmBADH2 gene using reported degenerate primers designed to conserved domains. Analysis of the translated amino acid sequence of LpBADH2 showed high degree of similarity (97.30%) with those of soybean homolog (GmBADH2). Conserved amino acid sequence of aldehyde dehydrogenase-super family were also identified in LpBADH2. Multiple sequence alignment of nucleotide sequences of LpBADH2 with those of related legumes using "ClustalW" revealed the presence of a single non-synonymous single nucleotide polymorphic (SNPs) and three synonymous SNP sites in LpBADH2. The substitution of the amino acid tyrosine in (fragrant genotypes) with phenyl alanine (non-fragrant genotypes) in protein coded by LpBADH2 appeared to be the cause for switch over from fragrance to non-fragrance in dolichos bean. These results are discussed in relation to strategies to breed dolichos bean cultivars with desired level of pod fragrance.

Screening for aroma in rice genotypes with African and Asian backgrounds

AbstractAromatic rice is highly preferred by consumers and has an important market worldwide. The demand for aromatic rice is high in East African countries, mainly in urban areas. Among the rice varieties that are grown in Burundi, few of them have a slight aroma which is not enough to satisfy the consumers’ demand and preference. There is no published report on the status of aroma in locally grown varieties and breeding lines in Burundi yet. This study aimed to identify aromatic genotypes that can be used in the breeding program to meet preferences of consumers. Two hundred fifteen genotypes were subjected to kompetitive allele‐specific PCR genotyping and sensory evaluation methods. Fifty‐three genotypes had the betaine aldehyde dehydrogenase (BADH2) gene for fragrance and displayed different levels of aroma expression. The sensory evaluation revealed two strongly aromatic genotypes, 43 moderately aromatic genotypes, 131 slightly aromatic genotypes, and 32 nonaromatic genotypes.The results of this study showed that BADH2 gene is significantly associated with rice aroma in accordance with previous reports. Furthermore, aroma and taste were positively and significantly correlated. Strongly aromatic genotypes (SUPA KATRIN and SUPA DE NYANZA –LAC) having the BADH2 gene for fragrance are of great interest for use in the breeding program to improve rice varieties to meet consumers' preferences in Burundi.

Genetic variation of Nang Thom Cho Dao rice variety based on whole genome sequencing

High-performance sequences are generating increasingly comprehensive catalogs of crop genetic variation. To make optimal use of this vast collection of data for research purposes, a robust and reproducible analytical pipeline discipline is required that is capable of accurately detecting and favoring variants. The entire genome sequencing data from the rice variety Nang Thom Cho Dao was analyzed using the appropriate bioinformatic pipeline. A total of 21 million reads with 6,6 GB of data were analyzed. SNPs and indels from the Nang Thom Cho Dao genome were found to be variable when compared to the Nipponbare reference rice genome. The result showed that the novel Indel of BADH2 gene in Nang Thom Cho Dao genome. The study will contribute valuable information to the development of genetic markers for rice breeding strategies using Nang Thom Cho Dao rice varieties.

Molecular analysis of aroma gene (BADH2) in Biriyanicheera: a tropical aromatic rice genotype from Kerala, India.

The aromatic rice cultivars sometimes show variation in aroma when they are grown in regions other than their normal traditional growing regions. An early maturing selection from a Kerala aromatic local landrace with short grains, named 'Biriyanicheera', when grown in normal tropical conditions was sufficiently fragrant. The present study focused on the analysis of aroma in 'Biriyanicheera' rice genotype through molecular methods. The seeds of two aromatic rice varieties viz., Biriyanicheera andGandhakasala (aromatic check) along with one non-aromatic rice variety Triveni (control) were used for the study. The BADH2 gene was amplified in all the three rice varieties. Upon sequencing the amplified PCR products of genomic DNA, the mutation in BADH2 gene was detected. The sequencing results of aromatic rice varieties revealed the presence of 8 base pair mutation in exon 7 in Biriyanicheera and Gandhakasaala, whereas this mutation was absent in the non-aromatic variety Triveni. Aroma production in Biriyanicheera variety is observed to be due to the similar mutation in BADH2 gene as that of the popular scented rice Basmati.

Development of Two Functional Markers of <i>Badh2</i> Gene in Guangxi Fragrant Rice

Fragrance in rice is one of the most important quality traits, which resulted from the loss of function of betaine aldehyde dehydrogenase ( Badh2 ) gene on chromosome 8. The mutation of  Badh2  leads to accumulation of 2-acetyl-1-pyrroline (2-AP), which is known as the main volatile in fragrant rice. At least 18 allelic variations have been identified in  Badh2  genes in rice. Marker assisted selection has proved to be an effective way of fragrant rice breeding. Traditional marker detection methods, such as Sanger sequencing or SSR molecular marker, are found to be low efficient. To develop a more dynamic method, we adopt Real-time PCR method to detect the common mutation site in Guangxi. In this study,  Badh2  gene of 40 fragrant rice accessions collected from Guangxi province was sequenced. Most of the fragrant rice accessions belonged to 806 bp deletion between exon 4-5 ( badh2-E4-5.1 ) and 8 bp deletion in exon 7 ( badh2-E7 ). Two Real-time PCR SNP molecular markers were developed, and were used to verify the 40 sequenced fragrant rice accessions. 93.75% of the detection results using Real-time PCR were consistent with the results of Sanger sequencing. Further, 50 local varieties were examined by Real-time PCR. A total of 24 accessions carry  badh-E4-5  allele and 22 accessions detected with  badh-E7 . The two functional SNP molecular markers common in Guangxi fragrant rice were developed and proved to be useful in rice breeding. These functional markers will improve the efficiency of fragrant rice breeding.

Detection of basmati rice using microsatellite markers

Basmati rice is a fine and aromatic rice grown mainly in certain areas of Punjab province in Pakistan. It has high demand in the international market and a source of earning foreign exchange via export. Adulteration of non-basmati rice grains is a major challenge to secure its export standards. Hence, the development of a simple and cost-effective method is necessary to screen the basmati and non-basmati rice samples. In this study, we have validated the efficiency of different molecular markers by screening seven unknown rice samples. Our results demonstrated that three markers namely RM1, RM19 and RM225 proved to be efficient microsatellite molecular markers that could be used to screen basmati and non-basmati rice samples. Further, these results are validated based on expression pattern of Badh2 gene among the basmati and non-basmati rice. Thus, this study provides a contribution towards development of a simple and cost-effective method for rapid screening of basmati rice.

Starch Morphology and Metabolomic Analyses Reveal That the Effect of High Temperature on Cooked Rice Elongation and Expansion Varied in Indica and Japonica Rice Cultivars

Rice (Oryza sativa L.) is mainly grouped into indica and japonica varieties. The aim of this study was to investigate the effect of temperature on cooked rice elongation, cooked rice expansion, and rice fragrance. This study was conducted in three growth temperature chambers with indica cultivar Basmati 385 (B385) and japonica cultivar Yunjingyou (YJY). Grains of B385 grown in low-temperature regimes had the highest cooked rice elongation and expansion, whereas the grains of YJY grown in high-temperature regimes had the highest cooked rice elongation and expansion. Starch granules of B385 grown in low-temperature regimes were more compact and bigger, compared to grains grown in medium- and high-temperature regimes. Conversely, the starch granules of YJY grown in high-temperature regimes were more compact and bigger, compared to those grown in medium- and low-temperature regimes. Metabolomic analyses showed that temperature affected the rice metabolome and revealed that cyclohexanol could be responsible for the differences observed in cooked rice elongation and expansion percentage. However, in both B385 and YJY, grains from low-temperature regimes had the highest 2-AP content and the lowest expression levels of the badh2 gene. The findings of this study will be useful to rice breeders and producers.

Variation for Grain Morphology, Molecular Diversity and Aroma Analysis in Specialty Rice of Assam

The nature and magnitude of genetic diversity of aromatic rice accessions collected from different agro climatic zones of Assam were evaluated in the present study . Grain morphology and molecular diversity was investigated for a collection of fourteen genotypes. In molecular genetic analysis 32 random SSR markers and 1 gene- based marker (Aroma-1) were included, out of which 16 informative SSR were employed for genetic analysis on the basis of their amplification. Molecular taxonomy and genetic divergence analysis revealed considerable variation among the tested aromatic lines. Of the 18 SSR variation in 14 genotypes, the value of PIC ranged from 0.1326 (RM337) to 0.5408 (RM496). The phylogenetic relations indicate presence of diverse genetic origin of the aromatic rice collection. Aroma analysis with gene based marker (Aroma- 1) amplified a unique band in Bokul Joha which is different from rest of the genotypes indicating probable presence of alternative allelic constitution of BADH2 gene for aroma.

The Determination of Aromatic Character of Several Local Rice Varieties using Phenotypic Analysis and Molecular DNA

The pandan scent in aromatic rice has been known as the result of 8 bp deletions and 3 Single Nucleotide Polymorphisms (SNPS) in BADH2 gene, which produce non-functional betaine aldehyde dehydrogenase (BADH) enzyme. Several DNA markers for aromatic character based on mutation in BADH2 gene have been developed. In our experiment, we analysed the presence of aromatic character in four local rice variety such as Merah Wangi, Pendok, Genjah Arum, and Mentik Wangi Susu using KOH method and DNA molecular method using three DNA markers to detect mutation that responsible for the development of aromatic character. Phenotype analysis using KOH method showed that Merah Wangi, Genjah Arum, and Mentik Wangi Susu produce pandan scents. PCR analysis using Bradbury and Badex7-5, and RM223 markers showed the presence of BADH2 mutation in Merah Wangi and Mentik Wangi Susu, whereas Pendok and Genjah Arum did not show BADH2 mutation using those used three markers. Our results indicate that among four investigated local rice, only Merah Wangi and Mentik Wangi Susu are categorized as aromatic rice whereas Pendok and Genjah Arum are non-aromatic.Keywords: genetic analysis, aromatic rice, specific markers, genetic mutation.