Biology subjects

Ellur, R. K.

Publications and source records attributed to Ellur, R. K..

3 recordsLinked to original sources

bioRxiv2025

Association of haplotypes of AAP family amino acid transporters with nitrogen response and nitrogen use efficiency in rice grown under hydroponics and field conditions

The low nitrogen use efficiency (NUE) of staple food crops like rice has both economic and environmental impact. Amino acids taken up from soil or synthesized in source tissues and transported to sink tissues influence plant development and NUE. Amino acid permeases (AAPs) mediate amino acid uptake and transport and influence plant development, yield and NUE. NUE is a complex trait critical for improving rice productivity under variable N supply. Amino acid permeases such as OsAAP3, OsAAP5, and OsAAP11 have been shown to function as negative regulators of NUE in Japonica rice, yet their roles in Indica rice remain to be fully elucidated. In this study, we evaluated selected Indica genotypes under contrasting N regimes--seedlings were tested under high nitrate (HN), high ammonium (HA), and low N (LN) conditions, and field performance was assessed under N120 (optimum N) and N0 (low N). Our aim was to relate performance differences to the SNP status in these three genes, thereby clarifying their influence on N uptake, assimilation, yield potential, and N stress adaptation. ARC 10799 had non-synonymous SNP in OsAAP3, OsAAP5 and OsAAP11. Rice accessions like "Local," "NCS901," and "Bhainsa Mundariya," showed superior biomass accumulation relative to MTU1010. Interestingly, the trend observed in the NUE calculated in seedling stage was similar to those proven in field evaluation and this proves that in general, genotypes with non-synonymous mutation in AAP3, AAP5 and AAP11 in comparison to Japonica showed better growth and N content. Data suggests an N induced regulation of physiological parameters and the changes in NUE parameters was at least in part, related to variation in biomass, plant height, photosynthesis and pigment content related parameters. The comparatively dissimilar trends in shown by different AAP haplotypes indicates the possibility of high or low correlation trait-wise, offering an opportunity to identify significant contrasts in a divergent set of AAP haplotypes. The previous reports and current findings opens new avenues and insights for improving rice yield, quality and NUE by changes in AAP haplotypes that occur naturally or created by precise genome editing.

plant biology↗

bioRxiv2023

Haplo-pheno association for OsNRT1.1 paralog in rice reveals superior haplogroup with high nitrate uptake efficiency

Haplotype-based breeding approaches hold promise for enhancing crop improvement strategies, allowing for targeted selection of superior genetic combinations to develop high-yielding and resilient varieties. The current study aimed at identification of NRT1.1 nitrate transporter haplotype that could serve as "donors" in haplotype-based breeding. We phenotyped 272 rice accessions in hydroponics with sufficient and low nitrogen (N) for nitrate uptake efficiency. By employing principal component and hierarchical cluster analysis, the accessions were grouped into N efficient, intermediate, and inefficient clusters. Haplotype analysis unveiled the presence of two haplogroups for OsNRT1.1A, three for OsNRT1.1B, and five for OsNRT1.1C. Through haplo-pheno association, the comparison of mean trait values revealed H2 and H3 as the superior haplotypes (SH) for OsNRT1.1A and OsNRT1.1B, respectively. In the case of OsNRT1.1C, H3 and H1 emerged as SH within the N-efficient cluster. Conversely, the inferior haplotypes (IH) consisted of H1 in OsNRT1.1A, H3 in OsNRT1.1B, and H3 and H2 in OsNRT1.1C within the N-inefficient cluster. However, relative expression of OsNRT1.1 (with specific paralogs) in contrasting rice accessions revealed that a few of the inferior accession exhibited higher expression levels in the root but lower in the shoot, which might have contributed to their N-inefficiency. Furthermore, amino acid change at position 403 (Isoleucine to Valine) in inferior accessions influences the active site OsNRT1.1C protein causing N-inefficiency. Ours is the first report on haplotype analysis of NRT1.1 gene demonstrating its genetic diversity, as well as its association with phenotype will have potential implications for improving nitrate uptake efficiency.

plant biology↗

bioRxiv2022

Rice Pan-genome Array (RPGA): an efficient genotyping solution for pan-genome-based accelerated crop improvement in rice

The advent of the pan-genome era has unraveled previously unknown genetic variation existing within diverse crop plants including rice. This untapped genetic variation is believed to account for a major portion of phenotypic variation existing in crop plants and might be responsible for missing heritability. However, the use of conventional single reference-guided genotyping often fails to capture large portion of this genetic variation leading to a reference bias. This makes it difficult to identify and utilize novel population/cultivar-specific genes for crop improvement. To overcome this challenge, we developed a rice pan-genome genotyping array (RPGA) includes 80K genome-wide SNPs which provides simple, user-friendly and cost-effective solution for rapid pan-genome-based genotyping in rice. The GWAS conducted using RPGA-SNP genotyping data of a rice diversity panel detected total of 42 loci, including previously known as well as novel genomic loci regulating grain size/weight traits in rice. Eight of the identified trait-associated loci (dispensable loci) could not be detected with conventional single reference genome-based GWAS and found to be missing from the commonly used Nipponbare reference genome. WD repeat-containing PROTEIN 12 gene underlying one of such dispensable locus on chromosome 7 (qLWR7) along with few other non-dispensable loci was subsequently detected using high-resolution QTL mapping confirming authenticity of RPGA-led GWAS. This demonstrates the potential of RPGA-based genotyping to overcome reference bias. Besides GWAS, the application of RPGA-based genotyping for natural allelic diversity and population structure analysis, seed purity and hybridity testing, ultra-high-density genetic map construction and chromosome level genome assembly, and marker-assisted foreground/background selection was successfully demonstrated. Based on these salient outcomes, a web application (http://www.rpgaweb.com) was also developed to provide easy to use platform for imputation of RPGA-based genotyping data using 3K Rice Reference Panel and subsequent GWAS in order to drive genetic improvement of rice.

genomics↗