scholarly journals Linked, if Not the Same, Mi-1 Homologues Confer Resistance to Tomato Powdery Mildew and Root-Knot Nematodes

2011 ◽  
Vol 24 (4) ◽  
pp. 441-450 ◽  
Author(s):  
Alireza Seifi ◽  
Isgouhi Kaloshian ◽  
Jack Vossen ◽  
Daidi Che ◽  
Kishor K. Bhattarai ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Gene Cluster ◽  
Chromosome 6 ◽  
R Genes ◽  
Near Isogenic Lines ◽  
Root Knot Nematodes ◽  
Isogenic Lines ◽  
Tomato Chromosome ◽  
Tomato Powdery Mildew

On the short arm of tomato chromosome 6, a cluster of disease resistance (R) genes have evolved harboring the Mi-1 and Cf genes. The Mi-1 gene confers resistance to root-knot nematodes, aphids, and whiteflies. Previously, we mapped two genes, Ol-4 and Ol-6, for resistance to tomato powdery mildew in this cluster. The aim of this study was to investigate whether Ol-4 and Ol-6 are homologues of the R genes located in this cluster. We show that near-isogenic lines (NIL) harboring Ol-4 (NIL-Ol-4) and Ol-6 (NIL-Ol-6) are also resistant to nematodes and aphids. Genetically, the resistance to nematodes cosegregates with Ol-4 and Ol-6, which are further fine-mapped to the Mi-1 cluster. We provide evidence that the composition of Mi-1 homologues in NIL-Ol-4 and NIL-Ol-6 is different from other nematode-resistant tomato lines, Motelle and VFNT, harboring the Mi-1 gene. Furthermore, we demonstrate that the resistance to both nematodes and tomato powdery mildew in these two NIL is governed by linked (if not the same) Mi-1 homologues in the Mi-1 gene cluster. Finally, we discuss how Solanum crops exploit Mi-1 homologues to defend themselves against distinct pathogens.

scholarly journals Maize nested introgression library provides evidence for the involvement of liguleless1 in resistance to northern leaf blight

2019 ◽  
Author(s):  
Judith M. Kolkman ◽  
Josh Strable ◽  
Kate Harline ◽  
Dallas E. Kroon ◽  
Tyr Wiesner-Hanks ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Association Analysis ◽  
Crop Improvement ◽  
Leaf Blight ◽  
Leaf Angle ◽  
Recurrent Parent ◽  
Near Isogenic Lines ◽  
Northern Leaf Blight ◽  
Leaf Architecture ◽  
Isogenic Lines

AbstractPlant disease resistance is largely governed by complex genetic architecture. In maize, few disease resistance loci have been characterized. Near-isogenic lines (NILs) are a powerful genetic tool to dissect quantitative trait loci (QTL). We analyzed an introgression library of maize near-isogenic lines (NILs), termed a nested NIL (nNIL) library for resistance to northern leaf blight (NLB) caused by the fungal pathogen Setosphaeria turcica. The nNIL library was comprised of 412 BC5F4 NILs that originated from 18 diverse donor parents and a common recurrent parent, B73. Single nucleotide polymorphisms identified through genotyping by sequencing (GBS) were used to define introgressions and for association analysis. NILs that conferred resistance and susceptibility to NLB were comprised of introgressions that overlapped known NLB QTL. Genome-wide association analysis and stepwise regression further resolved five QTL regions, and implicated several candidate genes, including Liguleless1 (Lg1), a key determinant of leaf architecture in cereals. Two independently-derived mutant alleles of lg1 inoculated with S. turcica showed enhanced susceptibility to NLB. In the maize nested association mapping population, leaf angle was positively correlated with NLB in five recombinant inbred line (RIL) populations, and negatively correlated with NLB in four RIL populations. This study demonstrates the power of a nNIL library combined with high density SNP coverage to resolve QTLs. Furthermore, the role of lg1 in leaf architecture and in resistance to NLB has important applications in crop improvement.Significance Statement (120 words)Understanding the genetic basis of disease resistance is important for crop improvement. We analyzed response to northern leaf blight (NLB) in a maize population consisting of 412 near-isogenic lines (NILs) derived from 18 diverse donor parents backcrossed to a recurrent parent, B73. NILs were genotyped by sequencing to detect introgressed segments. We identified NILs with greater resistance or susceptibility to NLB than B73. Genome-wide association analysis, coupled with stepwise regression, identified 5 candidate loci for NLB resistance, including the liguleless1 gene. The LIGULELESS1 transcription factor is critical in development of the leaf ligular region and influences leaf angle. We found that liguleless1 mutants are significantly more susceptible to NLB, uncovering a pleiotropic role for liguleless1 in development and disease resistance.

scholarly journals Tomato Defense to Oldium neolycopersici: Dominant OI Genes Confer Isolate-Dependent Resistance Via a Different Mechanism Than Recessive oI-2

2005 ◽  
Vol 18 (4) ◽  
pp. 354-362 ◽  
Author(s):  
Yuling Bai ◽  
Ron van der Hulst ◽  
Guusje Bonnema ◽  
Thierry C. Marcel ◽  
Fien Meijer-Dekens ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Resistance Mechanism ◽  
Recessive Gene ◽  
Defense Responses ◽  
Oidium Neolycopersici ◽  
Mechanism Of Resistance ◽  
Tomato Chromosome ◽  
Tomato Powdery Mildew ◽  
Important Disease

Tomato powdery mildew caused by Oidium neolycopersici has become a globally important disease of tomato (Lycopersicon esculentum). To study the defense responses of tomato triggered by tomato powdery mildew, we first mapped a set of resistance genes to O. neolycopersici from related Lycopersicon species. An integrated genetic map was generated showing that all the dominant resistance genes (Ol-1, Ol-3, Ol-4, Ol-5, and Ol-6) are located on tomato chromosome 6 and are organized in three genetic loci. Then, near-isogenic lines (NIL) were produced that contain the different dominant Ol genes in a L. esculentum genetic background. These NIL were used in disease tests with local isolates of O. neolycopersici in different geographic locations, demonstrating that the resistance conferred by different Ol genes was isolate-dependent and, hence, may be race-specific. In addition, the resistance mechanism was analyzed histologically. The mechanism of resistance conferred by the dominant Ol genes was associated with hypersensitive respo-nse, which varies in details depending on the Ol-gene in the NIL, while the mechanism of resistance governed by the recessive gene ol-2 on tomato chromosome 4 was associated with papillae formation.

scholarly journals Assessment of potentiality of known bacterial blight resistant genes against Xanthomonas oryzae pv. oryzae pathotypes exist in Bangladesh

2021 ◽  
Vol 6 (3) ◽  
pp. 257-267
Author(s):  
Md. Mahbubul Haque ◽  
Md. Mostafa Masud ◽  
Md. Mokarram Hossain ◽  
Md. Mamunur Rashid ◽  
Md. Zahangir Alam ◽  
...  
Keyword(s):  
Host Resistance ◽  
Bacterial Blight ◽  
Xanthomonas Oryzae ◽  
R Gene ◽  
R Genes ◽  
Near Isogenic Lines ◽  
Rice Varieties ◽  
Isogenic Lines ◽  
Resistant Genes ◽  
Resistance Reaction

Bacterial blight (BB) caused by X. oryzae pv. oryzae is a destructive disease of rice and causes 30-50% losses to rice depending on the outbreak. Development BB resistant rice varieties have long been considered as one of the most effective approach to control the disease. However, the durability of host resistance is breaking down due to the change of pathotypes of X. oryzae pv. oryzae globally. Pathotypic analyses of 239 X. oryzae pv. oryzae Bangladeshi isolates on Near Isogenic Lines (NILs) containing resistance (R) gene (s) revealed the existence of eight pathotypes of X. oryzae pv. oryzae. Among eight pathotypes, pathotypes IV and V were considered as major comprising  maximum number of isolates, (30.13% and 23.01%, respectively), whereas pathotype VIII considered as minor consisting only 2.51% of total isolates. Pathotype, I showed highest virulence or aggressiveness compatible with all NILs, whereas pathotype VIII exhibited lowest virulence to these NILs. Bacterial blight resistant genes viz. Xa1 (75.00%), Xa11 (62.50%) and Xa21 (50.00%) showed resistance to most of the pathotypes while Xa4 performed worst as compared to all others R-genes. In pyramid lines, IRBBB63 (Xa5+Xa7+Xa13) and IRBB57 (Xa5+Xa7 +Xa21) showed resistance reaction and IRBB61 (Xa4+Xa5+Xa7), IRBB60 (Xa4+Xa5+Xa13+Xa21), IRBB54 (Xa5+Xa21), and IRBB53 (Xa4+Xa21) showed susceptible reaction to X. oryzae pv. oryzae pathotypes. These results collectively indicated the deployment of Xa1, Xa11, Xa4, Xa5, Xa7, Xa13 and Xa21 either alone or in combination against BB would be a best choice for the development of BB resistant rice varieties in Bangladesh.

Development of wheat near-isogenic lines for powdery mildew resistance

2005 ◽  
Vol 110 (4) ◽  
pp. 640-648 ◽  
Author(s):  
Ronghua Zhou ◽  
Zhendong Zhu ◽  
Xiuying Kong ◽  
Naxin Huo ◽  
Qingzhen Tian ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Near Isogenic Lines ◽  
Mildew Resistance ◽  
Isogenic Lines

scholarly journals Powdery Mildew-Induced Hormonal and Photosynthetic Changes in Barley Near Isogenic Lines Carrying Various Resistant Genes

2020 ◽  
Vol 21 (12) ◽  
pp. 4536 ◽  
Author(s):  
Diana Saja ◽  
Anna Janeczko ◽  
Balázs Barna ◽  
Andrzej Skoczowski ◽  
Michał Dziurka ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Post Inoculation ◽  
Near Isogenic Lines ◽  
Leaf Reflectance ◽  
Isogenic Lines ◽  
Fluorescence Measurements ◽  
Resistant Genes ◽  
Psii Activity

The present work focused on the characterization of some physiological mechanisms activated upon powdery mildew inoculation of the susceptible barley cultivar Ingrid and its near-isogenic lines (NILs) carrying various resistant genes (Mla, Mlg and mlo). After inoculation with Blumeria graminis f. sp. hordei (Bgh), measurements of leaf reflectance and chlorophyll a fluorescence were performed 3 and 7 day post-inoculation (dpi), while hormone assays were made 7 dpi. Bgh-inoculated resistant genotypes were characterized by lowered leaf reflectance parameters that correlated with carotenoids (CRI) and water content (WBI) in comparison to inoculated Ingrid. The PSII activity (i.e., Fv/Fm, ETo/CSm and P.I.ABS) strongly decreased in susceptible Ingrid leaves when the disease symptoms became visible 7 dpi. In Mla plants with visible hypersensitive spots the PSII activity decreased to a lesser extent. Inoculation resulted in a very slight decrease of photosynthesis at later stage of infection in Mlg plants, whereas in resistant mlo plants the PSII activity did not change. Chlorophyll a fluorescence measurements allowed presymptomatic detection of infection in Ingrid and Mla. Changes in the homeostasis of 22 phytohormones (cytokinins, auxins, gibberellins and the stress hormones JA, SA and ABA) in powdery mildew inoculated barley are discussed in relation to resistance against this biotrophic pathogen.

Sign in / Sign up

Export Citation Format

Share Document