High night temperature (HNT) causes substantial yield loss in rice (Oryza sativa L.). In this study, the physiological processes related to flag leaf dark respiration (Rn) and grain filling under HNT ...were explored in a multi‐parent advanced generation intercross population developed for heat tolerance (MAGICheat) along with selected high temperature tolerant breeding lines developed with heat‐tolerant parents. Within a subset of lines, flag leaf Rn under HNT treatment was related to lower spikelet number per panicle and thus reduced yield. HNT enhanced the nighttime reduction of non‐structural carbohydrates (NSC) in stem tissue, but not in leaves, and stem nighttime NSC reduction was negatively correlated with yield. Between heading and harvest, the major difference in NSC concentration was found for starch, but not for soluble sugar. HNT weakened the relationship between NSC remobilization and harvest index at both the phenotypic and genetic level. By using genome‐wide association studies, an invertase inhibitor, MADS box transcription factors and a UDP‐glycosyltransferase that were identified as candidate genes orchestrating stem NSC remobilization in the control treatment were lost under HNT. With the identification of physiological and genetic components related to rice HNT response, this study offers promising prebreeding materials and trait targets to sustain yield stability under climate change.
Physiological response to high night temperature (HNT) was explored in rice (Oryza sativa L.) heat prebreeding lines. In stems, nighttime reduction of non‐structural carbohydrates, as well as starch remobilization between heading and harvest, was affected by HNT and correlated with yield.
Summary
Cicer arietinum L. (chickpea) is the third most important food legume crop. We have generated the draft sequence of a desi‐type chickpea genome using next‐generation sequencing platforms, ...bacterial artificial chromosome end sequences and a genetic map. The 520‐Mb assembly covers 70% of the predicted 740‐Mb genome length, and more than 80% of the gene space. Genome analysis predicts the presence of 27 571 genes and 210 Mb as repeat elements. The gene expression analysis performed using 274 million RNA‐Seq reads identified several tissue‐specific and stress‐responsive genes. Although segmental duplicated blocks are observed, the chickpea genome does not exhibit any indication of recent whole‐genome duplication. Nucleotide diversity analysis provides an assessment of a narrow genetic base within the chickpea cultivars. We have developed a resource for genetic markers by comparing the genome sequences of one wild and three cultivated chickpea genotypes. The draft genome sequence is expected to facilitate genetic enhancement and breeding to develop improved chickpea varieties.
In this study, we used 2.9 million single nucleotide polymorphisms (SNP) and 393,429 indels derived from whole genome sequences of 591 rice landraces to determine the genetic basis of cooked and raw ...grain length, width and shape using genome-wide association study (GWAS). We identified a unique fine-mapped genetic region GWi7.1 significantly associated with cooked and raw grain width. Additionally, GWi7.2 that harbors GL7/GW7 a cloned gene for grain dimension was found. Novel regions in chromosomes 10 and 11 were also found to be associated with cooked grain shape and raw grain width, respectively. The indel-based GWAS identified fine-mapped genetic regions GL3.1 and GWi5.1 that matched synteny breakpoints between indica and japonica. GL3.1 was positioned a few kilobases away from GS3, a cloned gene for cooked and raw grain lengths in indica. GWi5.1 found to be significantly associated with cooked and raw grain width. It anchors upstream of cloned gene GW5, which varied between indica and japonica accessions. GWi11.1 is present inside the 3'-UTR of a functional gene in indica that corresponds to a syntenic break in chromosome 11 of japonica. Our results identified novel allelic structural variants and haplotypes confirmed using single locus and multilocus SNP and indel-based GWAS.
Foxtail millet (Setariaitalica L.) is a tractable experimental model crop for studying functional genomics of millets and bioenergy grasses. But the limited availability of genomic resources, ...particularly expressed sequence-based genic markers is significantly impeding its genetic improvement. Considering this, we attempted to develop EST-derived-SSR (eSSR) markers and utilize them in germplasm characterization, cross-genera transferability and in silico comparative mapping. From 66,027 foxtail millet EST sequences 24,828 non-redundant ESTs were deduced, representing ~16 Mb, which revealed 534 (~2%) eSSRs in 495 SSR containing ESTs at a frequency of 1/30 kb. A total of 447 pp were successfully designed, of which 327 were mapped physically onto nine chromosomes. About 106 selected primer pairs representing the foxtail millet genome showed high-level of cross-genera amplification at an average of ~88% in eight millets and four non-millet species. Broad range of genetic diversity (0.02-0.65) obtained in constructed phylogenetic tree using 40 eSSR markers demonstrated its utility in germplasm characterizations and phylogenetics. Comparative mapping of physically mapped eSSR markers showed considerable proportion of sequence-based orthology and syntenic relationship between foxtail millet chromosomes and sorghum (~68%), maize (~61%) and rice (~42%) chromosomes. Synteny analysis of eSSRs of foxtail millet, rice, maize and sorghum suggested the nested chromosome fusion frequently observed in grass genomes. Thus, for the first time we had generated large-scale eSSR markers in foxtail millet and demonstrated their utility in germplasm characterization, transferability, phylogenetics and comparative mapping studies in millets and bioenergy grass species.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Brown planthopper (BPH) is a phloem sap-sucking insect pest of rice which causes severe yield loss. We cloned the BPH18 gene from the BPH-resistant introgression line derived from the wild rice ...species Oryza australiensis. Map-based cloning and complementation test revealed that the BPH18 encodes CC-NBS-NBS-LRR protein. BPH18 has two NBS domains, unlike the typical NBS-LRR proteins. The BPH18 promoter::GUS transgenic plants exhibited strong GUS expression in the vascular bundles of the leaf sheath, especially in phloem cells where the BPH attacks. The BPH18 proteins were widely localized to the endo-membranes in a cell, including the endoplasmic reticulum, Golgi apparatus, trans-Golgi network, and prevacuolar compartments, suggesting that BPH18 may recognize the BPH invasion at endo-membranes in phloem cells. Whole genome sequencing of the near-isogenic lines (NILs), NIL-BPH18 and NIL-BPH26, revealed that BPH18 located at the same locus of BPH26. However, these two genes have remarkable sequence differences and the independent NILs showed differential BPH resistance with different expression patterns of plant defense-related genes, indicating that BPH18 and BPH26 are functionally different alleles. These findings would facilitate elucidation of the molecular mechanism of BPH resistance and the identified novel alleles to fast track breeding BPH resistant rice cultivars.
Chickpea (Cicer arietinum L.) is an important pulse legume crop. We previously reported a draft genome assembly of the desi chickpea cultivar ICC 4958. Here we report an advanced version of the ICC ...4958 genome assembly (version 2.0) generated using additional sequence data and an improved genetic map. This resulted in 2.7-fold increase in the length of the pseudomolecules and substantial reduction of sequence gaps. The genome assembly covered more than 94% of the estimated gene space and predicted the presence of 30,257 protein-coding genes including 2230 and 133 genes encoding potential transcription factors (TF) and resistance gene homologs, respectively. Gene expression analysis identified several TF and chickpea-specific genes with tissue-specific expression and displayed functional diversification of the paralogous genes. Pairwise comparison of pseudomolecules in the desi (ICC 4958) and the earlier reported kabuli (CDC Frontier) chickpea assemblies showed an extensive local collinearity with incongruity in the placement of large sequence blocks along the linkage groups, apparently due to use of different genetic maps. Single nucleotide polymorphism (SNP)-based mining of intra-specific polymorphism identified more than four thousand SNPs differentiating a desi group and a kabuli group of chickpea genotypes.
Tomato Genomic Resources Database (TGRD) allows interactive browsing of tomato genes, micro RNAs, simple sequence repeats (SSRs), important quantitative trait loci and Tomato-EXPEN 2000 genetic map ...altogether or separately along twelve chromosomes of tomato in a single window. The database is created using sequence of the cultivar Heinz 1706. High quality single nucleotide polymorphic (SNP) sites between the genes of Heinz 1706 and the wild tomato S. pimpinellifolium LA1589 are also included. Genes are classified into different families. 5'-upstream sequences (5'-US) of all the genes and their tissue-specific expression profiles are provided. Sequences of the microRNA loci and their putative target genes are catalogued. Genes and 5'-US show presence of SSRs and SNPs. SSRs located in the genomic, genic and 5'-US can be analysed separately for the presence of any particular motif. Primer sequences for all the SSRs and flanking sequences for all the genic SNPs have been provided. TGRD is a user-friendly web-accessible relational database and uses CMAP viewer for graphical scanning of all the features. Integration and graphical presentation of important genomic information will facilitate better and easier use of tomato genome. TGRD can be accessed as an open source repository at http://59.163.192.91/tomato2/.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The prominent attributes of foxtail millet (Setaria italica L.) including its small genome size, short life cycle, inbreeding nature, and phylogenetic proximity to various biofuel crops have made ...this crop an excellent model system to investigate various aspects of architectural, evolutionary and physiological significances in Panicoid bioenergy grasses. After release of its whole genome sequence, large-scale genomic resources in terms of molecular markers were generated for the improvement of both foxtail millet and its related species. Hence it is now essential to congregate, curate and make available these genomic resources for the benefit of researchers and breeders working towards crop improvement. In view of this, we have constructed the Foxtail millet Marker Database (FmMDb; http://www.nipgr.res.in/foxtail.html), a comprehensive online database for information retrieval, visualization and management of large-scale marker datasets with unrestricted public access. FmMDb is the first database which provides complete marker information to the plant science community attempting to produce elite cultivars of millet and bioenergy grass species, thus addressing global food insecurity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The textural attributes of cooked rice determine palatability and consumer acceptance. Henceforth, understanding the underlying genetic basis is pivotal for the genetic improvement of preferred ...textural attributes in breeding programs. We characterized diverse set of 236
accessions from 37 countries for textural attributes, which includes adhesiveness (ADH), hardness (HRD), springiness (SPR), and cohesiveness (COH) as well as amylose content (AC). A set of 147,692 high quality SNPs resulting from genotyping data of 700K high Density Rice Array (HDRA) derived from the
diversity panels of 218 lines were retained for marker-trait associations of textural attributes using single-locus (SL) genome wide association studies (GWAS) which resulted in identifying hotspot on chromosome 6 for AC and ADH attributes. Four independent multi-locus approaches (ML-GWAS) including FASTmrEMMA, pLARmEB, mrMLM, and ISIS_EM-BLASSO were implemented to dissect additional loci of major/minor effects influencing the rice texture and to overcome limitations of SL-based GWAS approach. In total 224 significant quantitative trait nucleotide (QTNs) were identified using ML-GWAS, of which 97 were validated with at least two out of the four multi-locus methods. The GWAS results were in accordance with the very significant negative correlation (
= -0.83) observed between AC and ADH, and the significant correlation exhibited by AC (
< 0.4) with HRD, SPR, and COH. The novel haplotypes and putative candidate genes influencing textural properties beyond AC will be a useful resource for deployment into the marker assisted program to capture consumer preferences influencing rice texture and palatability.
While considerable breeding effort has focused on increasing the yields of staple crops such as rice and the levels of micronutrients such as iron and zinc, breeding to address the problems of the ...double‐burden of malnutrition has received less attention. Pigmented rice has higher nutritional value and greater health benefits compared to white rice. However, the genetic associations underlying pericarp coloration and accumulation of nutritionally valuable compounds is still poorly understood. Here we report the targeted genetic analysis of 364 rice accessions, assessing the genetic relationship between pericarp coloration (measured using multi‐spectral imaging) and a range of phenolic compounds with potential nutritional and health‐promoting characteristics. A genome‐wide association study resulted in the identification of over 280 single nucleotide polymorphisms (SNPs) associated with the traits of interest. Many of the SNPs were associated with more than one trait, colocalization occurring between nutritional traits, and nutritional and color‐related traits. Targeted association analysis identified 67 SNPs, located within 52 candidate genes and associated with 24 traits. Six haplotypes identified within the genes Rc/bHLH17 and OsIPT5 indicated that these genes have an important role in the regulation of a wide range of phenolic compounds, and not only those directly conferring pericarp color. These identified genetic linkages between nutritionally valuable phenolic compounds and pericarp color present not only a valuable resource for the enhancement of the nutritional value of rice but an easy method of selection of suitable genotypes.
Core Idea
Rc/bHLH17 and OsIPT5 are associated with a range of nutritionally valuable compounds.
Additional rice candidate genes associated with nutritional value were identified.
Linkages between color‐related phenotypes and nutritional content were found.
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