Breeding Strategies and Challenges in the Improvement of Blast Disease Resistance in Finger Millet. A Current Review

Climate change has significantly altered the biodiversity of crop pests and pathogens, posing a major challenge to sustainable crop production. At the same time, with the increasing global population, there is growing pressure on plant breeders to secure the projected food demand by improving the prevailing yield of major food crops. Finger millet is an important cereal crop in southern Asia and eastern Africa, with excellent nutraceutical properties, long storage period, and a unique ability to grow under arid and semi-arid environmental conditions. Finger millet blast disease caused by the filamentous ascomycetous fungus Magnaporthe oryzae is the most devastating disease affecting the growth and yield of this crop in all its growing regions. The frequent breakdown of blast resistance because of the susceptibility to rapidly evolving virulent genes of the pathogen causes yield instability in all finger millet-growing areas. The deployment of novel and efficient strategies that provide dynamic and durable resistance against many biotypes of the pathogen and across a wide range of agro-ecological zones guarantees future sustainable production of finger millet. Here, we analyze the breeding strategies currently being used for improving resistance to disease and discuss potential future directions toward the development of new blast-resistant finger millet varieties, providing a comprehensive understanding of promising concepts for finger millet breeding. The review also includes empirical examples of how advanced molecular tools have been used in breeding durably blast-resistant cultivars. The techniques highlighted are cost-effective high-throughput methods that strongly reduce the generation cycle and accelerate both breeding and research programs, providing an alternative to conventional breeding methods for rapid introgression of disease resistance genes into favorable, susceptible cultivars. New information and knowledge gathered here will undoubtedly offer new insights into sustainable finger millet disease control and efficient optimization of the crop’s productivity.

Download Full-text

Identification of Blast Resistant Genotypes among Drought Tolerant Finger Millet in Uganda

East African Journal of Agriculture and Biotechnology ◽

10.37284/eajab.2.1.235 ◽

2020 ◽

Vol 2 (1) ◽

pp. 58-70

Author(s):

John Charles Aru ◽

Nelson Wanyera ◽

Patrick Okori ◽

Paul Gibson

Keyword(s):

Crop Production ◽

Finger Millet ◽

Agricultural Research ◽

Cropping Systems ◽

Blast Resistance ◽

Hot Spot ◽

Breeding Strategy ◽

Blast Disease ◽

Eastern Africa ◽

Drought Tolerant

Finger millet is an important food security crop among many subsistence farmers living in marginal and especially semi-arid regions of Eastern Africa. However, crop production is affected mainly by terminal drought and blast disease caused by fungus Pyricularia grisea. Both collectively lead to over 90% grain yield loss depending on environmental conditions, cropping systems and varietal differences. Therefore, resistance breakdown remains high owing to variability in the blast pathogen and weather conditions. Stable varieties should possess both blast resistance and drought. In order to initiate breeding for multiple resistance to blast on drought-tolerant background, a study was conducted to identify variability for blast resistance from adapted germplasm as an initial step in developing a breeding strategy for incorporating resistance. Thirty genotypes from drought-prone agro-ecologies and including mini core germplasm from NARO-NaSARRI national Finger Millet improvement programme were assessed. They were screened using a local virulent pathogen isolate (NGR1) from Ngora, representing Teso major farming system and is a hot spot for the blast. The screening was under controlled conditions from in Makerere University Agricultural Research Institute (MUARIK) in 2012b. The results showed significance (p<0.01) for Area Under Disease Progressive Curve (AUDPC). Subsequently, the study identified IE927, Seremi1, Seremi3, Sec220 and Kabale as highly resistant to foliar blast infection comparable to Gulu-E a standard broad-spectrum resistant check and they could be used to improve finger millet for blast resistance. Meanwhile DR33, IE9 and IE2576 as most susceptible compared to non-race -specific susceptible check E11 from Uganda.

Download Full-text

Farmers’ knowledge and perception of finger millet blast disease and its control practices in western Kenya

CABI Agriculture and Bioscience ◽

10.1186/s43170-021-00033-y ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Wilton Mbinda ◽

Agnes Kavoo ◽

Fredah Maina ◽

Margaret Odeph ◽

Cecilia Mweu ◽

...

Keyword(s):

Finger Millet ◽

Management Practices ◽

Smallholder Farmers ◽

Descriptive Analysis ◽

Wide Distribution ◽

Blast Disease ◽

Eastern Africa ◽

Planting Density ◽

Global Food Security ◽

Disease Occurrence

Abstract Background Finger millet blast disease, caused by Pyricularia oryzae, is a serious constrain of finger millet production which is threatening global food security especially to the resource poor smallholder farmers in arid and semi-arid regions. The disease adversely affects finger millet production and consumption due to its wide distribution and destruction in all finger millet growing areas of southern Asia and eastern Africa. Here, we present a study that investigated the occurrence, impact, risk factors and farmers’ knowledge and perceptions of finger millet blast in Kenya. Methods We surveyed blast disease occurrence and interviewed farmers in Bungoma and Kisii Counties of Kenya during March–April 2019. Data were analysed using SPSS statistical program. Descriptive analysis was done by calculating means, percentages, frequencies, and standard errors. Comparative statistics, chi-square and t-tests, were used to evaluate differences existing among the farm characteristics and socio-demographics and the knowledge and perceptions of blast disease and its management practices. Results Our results show that blast disease is prevalent in all surveyed areas and adversely affects the productivity of the crop leading to poor yields. The disease occurrence varied from 92 to 98%, and was significantly higher in the major finger millet growing areas compared to the minor ones. Blast occurrence was associated with rainfall, altitude, planting density, intercropping and other farming practices. In all the surveyed regions, farmers had little knowledge about blast disease identification, its detection and spread. Further, the farmers’ awareness of blast disease control was inconsistent with established practices. Conclusions Our results show mitigation of finger millet blast disease should aim at improving farmers’ adoption of best practices through development of acceptable blast-resistant finger millet varieties, use of sustainable disease management practices, fostering linkages and creating new partnerships in the production-supply chain and maintaining a functional seed system. Findings from this study provide essential insights for effective decision making and management of the disease. This is fundamental to sustainable and secure food and income for finger millet growing farmers in Kenya.

Download Full-text

Level of Endogenous Jasmonate is Critical for Durable Broad-Spectrum Disease Resistance Against Rice Blast in a Japonica Rice Variety, Ziyu44

10.21203/rs.3.rs-571828/v1 ◽

2021 ◽

Author(s):

Xingyu An ◽

Hui Zhang ◽

Jinlu Li ◽

Rui Yang ◽

Qianchun Zeng ◽

...

Keyword(s):

Disease Resistance ◽

Signaling Pathway ◽

Broad Spectrum ◽

Rice Blast ◽

Blast Resistance ◽

Rice Variety ◽

Blast Disease ◽

Japonica Rice ◽

Mycelium Growth ◽

Broad Spectrum Resistance

Abstract Background: The molecular mechanism of durable and broad-spectrum resistance to rice blast disease in japonica rice variety is still very little known. Ziyu44, a local japonica rice variety in Yunnan Province of China, has shown durable broad-spectrum blast resistance for more than 30 years, and provides an opportunity for us to explore the molecular basis of broad-spectrum resistance to rice blast in japonica rice variety.Methods and Results: We conducted a comparative study of mycelium growth, aposporium formation, the accumulation of salicylate(SA), jasmonate(JA) and H2O2, the expression of SA- and JA-associated genes between Ziyu44 and susceptible variety Jiangnanxiangnuo (JNXN) upon M. oryzae infection. We found that appressorium formation and invasive hyphae extention were greatly inhibited in Ziyu 44 leaves compared with that in JNXN leaves. Both Ziyu 44 and JNXN plants maintained high levels of baseline SA and did not show increased accumulation of SA after inoculation with M. oryzae, while the levels of baseline JA in Ziyu 44 and JNXN plants were relatively low, and the accumulation of JA exhibited markedly increased in Ziyu 44 plants upon M. oryzae infection. The expression levels of key genes involving JA and SA signaling pathway OsCOI1b, OsNPR1, OsMPK6 as well as pathogenesis-related (PR) genes OsPR1a, OsPR1b and OsPBZ1, were markedly up-regulated in Ziyu44. Conclusions: The level of endogenous JA is critical for synchronous activation of SA and JA signaling pathway, up-regulating PR gene expression and enhancing disease resistance against rice blast in Ziyu44.

Download Full-text

Investigating the biology of rice blast disease and prospects for durable resistance

10.19103/as.2021.0092.23 ◽

2021 ◽

pp. 643-680

Author(s):

Vincent M. Were ◽

◽

Nicholas J. Talbot ◽

Keyword(s):

Cell Biology ◽

Rice Blast ◽

Plant Pathogens ◽

Blast Resistance ◽

Durable Resistance ◽

Rice Blast Disease ◽

Blast Disease ◽

Global Food Security ◽

Major Resistance Genes ◽

Effector Secretion

There are important biological process involved in rice blast disease that are now well-studied during the early events in plant infection which include: the cell biology of appressorium formation, the biology of invasive growth and effector secretion, the two distinct mechanisms of effector secretion, the nature of the plant-pathogen interface, PAMP-triggered immunity modulation by secreted effectors and effector-triggered immunity and blast resistance. The devastating losses caused by the blast fungus have been documented in most grasses, but this chapter discusses the use of major resistance genes to rice blast and wheat blast disease as an emerging threat to global food security. This chapter also highlights an emerging approach to breed for durable resistance to plant pathogens using gene editing technologies with an example: CRISPR-Cas9 mutagenesis of dominant S-genes for disease control.

Download Full-text

Combining Ability Analysis of Blast Disease Resistance and Agronomic Traits in Finger Millet [Eleusine coracana (L.) Gaertn]

Journal of Agricultural Science ◽

10.5539/jas.v8n11p138 ◽

2016 ◽

Vol 8 (11) ◽

pp. 138 ◽

Cited By ~ 1

Author(s):

Lawrence Owere ◽

Pangirayi Tongoona ◽

John Derera ◽

Nelson Wanyera

Keyword(s):

Disease Resistance ◽

Combining Ability ◽

Finger Millet ◽

Gene Action ◽

Agronomic Traits ◽

The Other ◽

Blast Disease ◽

Additive Gene Action ◽

Gene Effects ◽

Additive Gene

Blast disease is the most important biotic constraint to finger millet production. Therefore disease resistant varieties are required. However, there is limited information on combining ability for resistance and indeed other agronomic traits of the germplasm in Uganda. This study was carried out to estimate the combining ability and gene effects controlling blast disease resistance and selected agronomic traits in finger millet. Thirty six crosses were generated from a 9 × 9 half diallel mating design. The seed from the 36 F1 crosses were advanced by selfing and the F2 families and their parents were evaluated in three replications. General combining ability (GCA) for head blast resistance and the other agronomic traits were all highly significant (p ≤ 0.01), whereas specific combining ability (SCA) was highly significant for all traits except grain yield and grain mass head-1. On partitioning the mean sum of squares, the GCA values ranged from 31.65% to 53.05% for head blast incidence and severity respectively, and 36.18% to 77.22% for the other agronomic traits measured. Additive gene effects were found to be predominant for head blast severity, days to 50% flowering, grain yield, number of productive tillers plant-1, grain mass head-1, plant height and panicle length. Non-additive gene action was predominant for number of fingers head-1, finger width and panicle width. The parents which contributed towards high yield were Seremi 2, Achaki, Otunduru, Bulo and Amumwari. Generally, highly significant additive gene action implied that progress would be made through selection whereas non-additive gene action could slow selection progress and indicated selection in the later generations.

Download Full-text

RFLP mapping of genes conferring complete and partial resistance to blast in a durably resistant rice cultivar.

Genetics ◽

10.1093/genetics/136.4.1421 ◽

1994 ◽

Vol 136 (4) ◽

pp. 1421-1434 ◽

Cited By ~ 1

Author(s):

G L Wang ◽

D J Mackill ◽

J M Bonman ◽

S R McCouch ◽

M C Champoux ◽

...

Keyword(s):

Partial Resistance ◽

Blast Resistance ◽

Durable Resistance ◽

Complex Trait ◽

Rice Cultivar ◽

Blast Disease ◽

Rflp Markers ◽

Japonica Rice ◽

Qualitative Resistance ◽

Ri Lines

Abstract Moroberekan, a japonica rice cultivar with durable resistance to blast disease in Asia, was crossed to the highly susceptible indica cultivar, CO39, and 281 F7 recombinant inbred (RI) lines were produced by single seed descent. The population was evaluated for blast resistance in the greenhouse and the field, and was analyzed with 127 restriction fragment length polymorphism (RFLP) markers. Two dominant loci associated with qualitative resistance to five isolates of the fungus were tentatively named Pi-5(t) and Pi-7(t). They were mapped on chromosomes 4 and 11, respectively. To identify quantitative trait loci (QTLs) affecting partial resistance, RI lines were inoculated with isolate PO6-6 of Pyricularia oryzae in polycyclic tests. Ten chromosomal segments were found to be associated with effects on lesion number (P < 0.0001 and LOD > 6.0). Three of the markers associated with QTLs for partial resistance had been reported to be linked to complete blast resistance in previous studies. QTLs identified in greenhouse tests were good predictors of blast resistance at two field sites. This study illustrates the usefulness of RI lines for mapping a complex trait such as blast resistance and suggests that durable resistance in the traditional variety, Moroberekan, involves a complex of genes associated with both partial and complete resistance.

Download Full-text

Synchronised regulation of disease resistance in primed finger millet plants against the blast disease

Biotechnology Reports ◽

10.1016/j.btre.2020.e00484 ◽

2020 ◽

Vol 27 ◽

pp. e00484

Author(s):

Savita Veeranagouda Patil ◽

Belur Satyan Kumudini ◽

Hosur Gnanaprakash Pushpalatha ◽

Savitha De Britto ◽

Shin-ichi Ito ◽

...

Keyword(s):

Disease Resistance ◽

Finger Millet ◽

Blast Disease

Download Full-text

A Genome-Wide Meta-Analysis of Rice Blast Resistance Genes and Quantitative Trait Loci Provides New Insights into Partial and Complete Resistance

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-21-7-0859 ◽

2008 ◽

Vol 21 (7) ◽

pp. 859-868 ◽

Cited By ~ 216

Author(s):

Elsa Ballini ◽

Jean-Benoît Morel ◽

Gaétan Droc ◽

Adam Price ◽

Brigitte Courtois ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Resistance Genes ◽

Quantitative Trait ◽

Rice Blast ◽

Blast Resistance ◽

Durable Resistance ◽

Rice Genome ◽

Blast Disease ◽

Trait Loci ◽

Blast Resistance Genes

The completion of the genome sequences of both rice and Magnaporthe oryzae has strengthened the position of rice blast disease as a model to study plant–pathogen interactions in monocotyledons. Genetic studies of blast resistance in rice were established in Japan as early as 1917. Despite such long-term study, examples of cultivars with durable resistance are rare, partly due to our limited knowledge of resistance mechanisms. A rising number of blast resistance genes and quantitative trait loci (QTL) have been genetically described, and some have been characterized during the last 20 years. Using the rice genome sequence, can we now go a step further toward a better understanding of the genetics of blast resistance by combining all these results? Is such knowledge appropriate and sufficient to improve breeding for durable resistance? A review of bibliographic references identified 85 blast resistance genes and approximately 350 QTL, which we mapped on the rice genome. These data provide a useful update on blast resistance genes as well as new insights to help formulate hypotheses about the molecular function of blast QTL, with special emphasis on QTL for partial resistance. All these data are available from the OrygenesDB database.

Download Full-text

Cloning and Function Analysis of a Novel Rice Blast Resistance Gene Pi65 in Japonica Rice

10.21203/rs.3.rs-762818/v1 ◽

2021 ◽

Author(s):

Lili Wang ◽

Zuobin Ma ◽

Houxiang Kang ◽

Shuang Gu ◽

Zhanna Mukhina ◽

...

Keyword(s):

Disease Resistance ◽

Resistance Gene ◽

Rice Blast ◽

Blast Resistance ◽

Rice Blast Disease ◽

Blast Disease ◽

Resistant Variety ◽

Japonica Rice ◽

Rice Blast Resistance ◽

Blast Resistance Gene

Abstract Rice blast seriously threatens rice production worldwide. Utilizing the rice blast resistance gene to breed the rice blast resistant varieties is one of the best ways to control rice blast disease. Using a map-based cloning strategy, here, we cloned a novel rice blast resistance gene, Pi65 from the resistant variety GangYu129 (abbreviated GY129, O. sativa japonica ). Overexpression of Pi65 in the susceptible variety LiaoXing1 (abbreviated LX1, O. sativa japonica ) enhanced rice blast resistance, while knockout of Pi65 in GY129 resulted in susceptible to rice blast disease. Pi65 encodes two transmembrane domains, with 15 LRR domains and one serine/threonine protein kinase catalytic domain, conferring resistance to isolates of M. oryzae collected from northeast China. There are sixteen amino acids differences between the Pi65 resistance and susceptible alleles. Compared with the Pi65 resistant allele, the susceptible allele deleted one LRR domain. Pi65 was constitutively expressed in whole plants, and it could be induce expressed in the early stage of M. oryzae infection . Transcriptome analysis revealed that numerous genes associated with disease resistance were specifically upregulated in GY129 24-hour post inoculation (HPI), on the contrary, the photosynthesis-and carbohydrate metabolism-related genes were particularly downregulated 24 HPI, demonstrating that the disease resistance associated genes has been activated in GY129 (carrying Pi65 ) after rice blast fungal infection, and the cellular basal and energy metabolism was inhibited simultaneously. Our study provides genetic resources for improving rice blast resistance as well as enriches the study of rice blast resistance mechanisms.

Download Full-text

Virulence Pattern of Pyricularia oryzae Pathotypes Towards Blast Monogenic Lines

Tropical Life Sciences Research ◽

10.21315/tlsr2021.32.3.8 ◽

2021 ◽

Vol 32 (3) ◽

pp. 147-160

Author(s):

Siti Norsuha Misman ◽

Mohd Shahril Firdaus Ab Razak ◽

Nur Syahirah Ahmad Sobri ◽

Latiffah Zakaria

Keyword(s):

Resistance Genes ◽

Rice Blast ◽

Blast Resistance ◽

Rice Variety ◽

Durable Resistance ◽

Peninsular Malaysia ◽

Pyricularia Oryzae ◽

Blast Disease ◽

Breeding Lines ◽

Virulence Pattern

Rice blast caused by Pyricularia oryzae (P. oryzae) is one of the most serious diseases infecting rice worldwide. In the present study, virulence pattern of six P. oryzae pathotypes (P0.0, P0.2, P1.0, P3.0, P7.0 and P9.0) identified from the blast pathogen collected in Peninsular Malaysia, were evaluated using a set of 22 IRRI-bred blast resistance lines (IRBL) as well as to determine the resistance genes involved. The information on the virulence of the blast pathotypes and the resistance genes involved is important for breeding of new rice variety for durable resistance against blast disease. The IRBL was established from 22 monogenic lines, harbouring 22 resistance genes [Pia, Pib, Pii, Pit, Pi3, Pi5(t), Pish, Pi1, Pik, Pik-s, Pik-m, Pik-h, Pik-p, Pi7(t), Pi9, Piz, Piz-5, Piz-t, Pi19, Pi20(t), Pita-2, and Pita=Pi4(t)]. Based on the disease severity patterns, the tested pathotypes were avirulence towards seven IRBLs [IRBLi-F5, IRBLk-Ka, IRBLkh-K3, IRBLz-Fu, IRBLsh-S, IRBLPi7 (t) and IRBL9-W] of which these IRBLs harbouring Pii, Pik, Pik-h, Piz, Pish, Pi7(t) and Pi9 resistance genes, respectively. Therefore, the results suggested that the seven IRBLs carrying seven resistance genes [Pii, Pik, Pik-h, Piz, Pish, Pi7(t) and Pi9] would be suitable candidates of resistance genes to be incorporated in new breeding lines to combat the current blast pathotypes in the field.

Download Full-text