Author: Xinyao He

Wheat blast: a new threat to food security

Xinyao He Pawan Singh (2020)

Wheat blast, caused by the Magnaporthe oryzae Triticum (MoT) lineage (synonym Pyricularia oryzae Triticum lineage), is a destructive disease in South America and Bangladesh. It is primarily a disease of wheat head, which can cause yield loss up to 100% under favorable disease conditions. The head infection results in complete or partial bleaching of the spike above the point of infection with either no grain or shriveled grain with low test weight. Due to low fungicide efficacy against the disease and lack of availability of resistant varieties, an integrated management program should be adopted to control this serious wheat disease. First of all, a convenient and specific diagnostic tool is needed for evaluating seed health and early detection in wheat field to initiate timely mitigation measures and thereby decreasing pathogen initial inoculum and dispersal. Second, we should have a better understanding of the epidemiology of the disease and develop a real-time disease monitoring and surveillance system to alert growers to apply management practices at an optimum time. Third, we need a better understanding of the infection biology of the fungus and its interaction with wheat plants at the tissue and molecular levels helpful for improving disease management. Fourth, breeding for resistance to wheat blast can be accelerated by using resistance genes such as 2NS translocation, Rmg8 and RmgGR119 or advanced genomic technology such as CRISPR-Cas. Fifth, integration of alternative disease management practices, such as biological control using antagonistic microorganisms or derivatives thereof to achieve sustainable approach for the management of wheat blast. Finally, a globally concerted effort is needed using open science and open data sharing approaches to prevent this seed- and air-borne plant disease’s widespread devastation of wheat crop. This comprehensive review updates our knowledge on wheat blast disease and discusses the approaches for its sustainable management for ensuring food and nutritional security of the ever-increasing global population.



Analysis of the Masked Metabolite of Deoxynivalenol and Fusarium Resistance in CIMMYT Wheat Germplasm

Xinyao He Masayo Kushiro (2017)

Fusarium head blight (FHB) causes significant grain loss and contamination of grains with harmful mycotoxins, especially deoxynivalenol (DON). Fusarium resistance and DON accumulation have been extensively investigated in various cultivars; however, the level of DON-3-O-glucoside (D3G) has not been as carefully studied. In this study, we measured accumulated DON and D3G levels in CIMMYT wheat elite germplasm using an analytical method validated in-house. Co-occurring nivalenol (NIV) and ergostrerol (ERG) were also analyzed. LC-MS/MS and LC-UV analyses were applied to the 50 CIMMYT elite wheat lines. D3G showed rather high correlation with DON (r = 0.82), while FHB symptoms showed slight correlation with DON and D3G (r = 0.36 and 0.32, respectively). D3G/DON ratio varied widely from 8.1 to 37.7%, and the ratio was not related with FHB resistance in this dataset.


Maize production Soil quality Gross margin Farmer perceptions Yields CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Investigation and genome-wide association study for Fusarium crown rot resistance in Chinese common wheat

Pawan Singh Xinyao He (2019)

Background: Fusarium crown rot (FCR) is a severe and chronic disease in common wheat and is able to cause serious yield loss and health problems to human and livestock.Results: Here, 234 Chinese wheat cultivars were evaluated in four greenhouse experiments for FCR resistance and genome-wide association studies (GWAS) were performed using the wheat 660K genotyping assay. The results indicated that most cultivars evaluated showed FCR disease index (DI) of 40-60, while some cultivars showed stably good FCR resistance (DI<30). GWAS identified 286 SNPs to be significantly associated with FCR resistance, of which 266, 6 and 8 were distributed on chromosomes 6A, 6B and 6D, respectively. The significant SNPs on 6A were located in a 7.0-Mb region containing 51 annotated genes. On the other hand, QTL mapping using a bi-parental population derived from UC1110 and PI610750 detected three QTLs on chromosomes 6A (explaining 7.77-10.17% of phenotypic variation), 2D (7.15-9.29%) and 2A (5.24-6.92%). The 6A QTL in the UC1110/PI610750 population falls into the same chromosomal region as those detected from GWAS, demonstrating its importance in Chinese materials for FCR resistance.Conclusion: This study could provide useful information for utilization of FCR-resistant wheat germplasm and further understanding of molecular and genetics basis of FCR resistance in common wheat.



Cloning and phylogenetic analysis of phytoene synthase 1 (Psy1) genes in common wheat and related species

Xinyao He Zhonghu He xianchun xia (2009)

Cloning and phylogenetic analysis of Psy1 genes in common wheat and its relatives would help to understand the genetic diversity and evolution of Psy1 gene in common wheat and its related species. In the present study, common wheat (AABBDD) and eight relative species, including T. urartu (AuAu), T. boeoticum (AmAm), T. monococcum (AmAm), Ae. speltoides (SS), Ae. tauschii (DD), T. dicoccoides (AABB), T. dicoccum (AABB) and T. spelta (AABBDD), were sampled for the isolation of novel alleles at Psy1‐A1, Psy1‐B1/Psy1‐S1 and Psy1‐D1 loci corresponding to common wheat Psy1 genes, and 27 new alleles were identified at these loci, designated Psy1‐A1f through Psy1‐A1k, Psy1‐A1m and Psy1‐A1n, Psy1‐B1h through Psy1‐B1m, Psy1‐S1a through Psy1‐S1c, Psy1‐D1a through Psy1‐D1j, respectively. The genes contained six exons and five introns, and the sequences of exons were more conserved compared with those of introns. The Psy1‐A1 genes encoded a polypeptide of 428 aminoacid residues, with one residue longer than those encoded by Psy1‐D1 genes. The Psy1‐B1/Psy1‐S1 genes encoded four types of polypeptides, with 421 (Psy1‐B1h through Psy1‐B1j, Psy1‐B1l), 427 (Psy1‐B1k, Psy1‐S1a and Psy1‐S1c), 428 (Psy1‐B1m), and 429 (Psy1‐S1b) aminoacid residues, respectively. Neighbor joining tree was generated based on the gene sequences of the 27 novel alleles and those of the 13 alleles reported previously in common wheat and its relatives. The phylogenetic tree consisted of two subtrees. The subtree I comprised 11 of 14 alleles at Psy1‐A1 locus, nine of 16 alleles at Psy1‐B1/Psy1‐S1 locus, and ten novel alleles at Psy1‐D1 locus, while the subtree II included the other three alleles at Psy1‐A1 locus, the remaining four Psy1‐B1 alleles and three Psy1‐S1 alleles. The alleles from different clusters showed high sequence divergences, indicated by various SNPs and InDels (insertion/deletion). The phylogenetic relationships of these allelic variants at the three loci in common wheat and its relatives also supported the hypothesis that common wheat was originated by recurrent hexaploidization events. In addition, 193 Chinese wheat cultivars with different yellow pigment contents were genotyped with two novel STS markers YP7D‐1 and YP7D‐2. The results indicated that 191 cultivars contained the allele Psy1‐D1a, and two had Psy1‐D1g.



Genetic mapping of resistance in hexaploid wheat for a quarantine disease

Xinyao He Carolina Sansaloni Ravi Singh (2018)

Karnal bunt (KB) of wheat, caused by Tilletia indica, is one of the greatest challenges to grain industry, not because of yield loss, but quarantine regulations that restrict international movement and trade of affected stocks. Genetic resistance is the best way to manage this disease. Although several different sources of resistance have been identified to date, very few of those have been subjected to genetic analyses. Understanding the genetics of resistance, characterization and mapping of new resistance loci can help in development of improved germplasm. The objective of this study was to identify and characterize resistance loci (QTL) in two independent recombinant inbred lines (RILs) populations utilizing different wheat lines as resistance donors. Elite CIMMYT wheat lines Blouk#1 and Huirivis#1 were used as susceptible female parents and WHEAR/KUKUNA/3/C80.1/3∗BATAVIA//2∗WBLL1 (WKCBW) and Mutus as moderately resistant male parents in Pop1 and Pop2 populations, respectively. Populations were evaluated for KB resistance in 2015–16 and 2016–17 cropping seasons at two seeding dates (total four environments) in Cd. Obregon, Mexico. Two stable QTL from each population were identified in each environment: QKb.cim-2B and QKb.cim-3D (Pop1), QKb.cim-3B1 and QKb.cim-5B2 (Pop2). Other than those four QTL, other QTL were detected in each population which were specific to environments: QKb.cim-5B1, QKb.cim-6A, and QKb.cim-7A (Pop1), QKb.cim-3B2, QKb.cim-4A1, QKb.cim-4A2, QKb.cim-4B, QKb.cim-5A1, QKb.cim-5A2, and QKb.cim-7A2 (Pop2). Among the four stable QTL, all but QKb.cim-3B1 were derived from the resistant parent. QKb.cim-2B and QKb.cim-3D in Pop1 and QKb.cim-3B1 and QKb.cim-5B2 in Pop2 explained 5.0–11.4% and 3.3–7.1% phenotypic variance, respectively. A combination of two stable QTL in each population reduced KB infection by 24–33%, respectively. Transgressive resistant segregants lines derived with resistance alleles from both parents in each population were identified. Single nucleotide polymorphism (SNP) markers flanking these QTL regions may be amenable to marker-assisted selection. The best lines from both populations (in agronomy, end-use quality and KB resistance) carrying resistance alleles at all identified loci, may be used for inter-crossing and selection of improved germplasm in future. Markers flanking these QTL may assist in selection of such lines.