Ecofriendly Management of Wheat Panicle Blast Caused by Magnaporthe oryzae triticum

In this study, three wheat varieties were tested to determine seed germination and the incidence of Magnaporthe oryzae triticum (MoT). Among these varieties, BARI Gom 24 (Prodip) wheat seed exhibited the highest seed germination rate (93%) but also had the highest incidence (30%) of MoT. To manage blast disease in an ecofriendly manner, seven treatments were employed: T1 = Control, T2 = Garlic clove extracts, T3 = Aloe vera leaf extracts, T4 = Black cumin seed extracts, T5 = Neem leaf extracts, T6 = Nativo 75 WG, and T7 = Provax 200 WP. The experiment was conducted using a Randomized Complete Block Design (RCBD) layout with three replications using Prodip wheat variety that exhibited highest MoT infection severity based on laboratory analysis among collected varieties. Data were collected on blast disease incidence (%), disease severity, and various growth and yield parameters of wheat. The experiment’s results indicated that among all the treatments, T7 (Seed treatment with Provax 200 WP) and T5 (Foliar spraying with Neem leaf extract) performed better in controlling blast disease in wheat. The lowest blast disease incidence (%) was observed with T7 (Provax 200 WP), with values of 7.86, 9.86, and 10.19 recorded during the milking stage, soft dough stage, and hard dough stage of wheat, respectively. T5 (Neem leaf extract) also demonstrated a statistically equivalent reduction in blast disease incidence (%). In terms of disease severity, T7 (Seed treatment with Provax 200 WP) showed the lowest values of 1.03, 1.23, and 1.63 during the milking stage, soft dough stage, and hard dough stage of wheat, respectively. Foliar spraying with neem leaf extract also exhibited similar result as of Provax 200 WP regarding panicle blast severity. As a result of these findings, it can be concluded that T5 (Neem leaf extract) is recommended as an ecofriendly management approach for blast disease in wheat.

Rapid Detection of Wheat Blast Pathogen Magnaporthe oryzae Triticum Pathotype Using Genome-Specific Primers and Cas12a-mediated Technology

Wheat blast,caused by the fungus Magnaporthe oryzae Triticum(MoT)pathotype,is a devastating disease persistent in South America and Bangladesh.Since MoT generally fails to cause visual symptoms in wheat until the heading stage when the infection would have advanced,disease control by fungicide application solely based on the detection of visual symptoms is ineffective.To develop an accurate and sensitive method to detect MoT at the seedling and vegetative stages for disease control,we sequenced the genomes of two MoT isolates from Brazil and identified two DNA fragments,MoT-6098 and MoT-6099,that are present in the MoT genome but not in the genome of the rice-infecting Magnaporthe oryzae Oryzae(MoO)pathotype.Using polymerase chain reaction(PCR),we confirmed the specificity of the two markers in 53 MoT and MoO isolates from South America and Bangladesh.To test the efficiency of the two markers,we first established a loop-mediated isothermal amplification(LAMP)method to detect MoT at isothermal conditions,without the use of a PCR machine.Following this,we used the Cas12a protein and guide RNAs(gRNAs)to target the MoT-6098 and MoT-6099 sequences.The activated Cas12a showed indiscriminate single-stranded deoxyribonuclease(ssDNase)activity.We then combined targetdependent Cas12a ssDNase activation with recombinase polymerase amplification(RPA)and nucleic acid lateral flow immunoassay(NALFIA)to develop a method that accurately,sensitively,and cost-effectively detects MoT-specific DNA sequences in infected wheat plants.This novel technique can be easily adapted for the rapid detection of wheat blast and other important plant diseases in the field.

Genetic sources and loci for wheat head blast resistance identified by genome-wide association analysis

The emergence and spread of wheat blast caused by fungal pathogen Magnaporthe oryzae pathotype Triticum is a threat to global wheat production.The resistance level and genetic loci for blast resistance in Chinese germplasm remain unknown.A panel of 266 bread wheat accessions from China,CIMMYTMexico and other countries was screened for head blast resistance under 12 field experiments in Bolivia and Bangladesh.Subsequently,a genome-wide association study was performed to understand the genetic basis of wheat blast resistance.The average blast index of all the accessions was 53.7%±12.7%,and 10 accessions including Chinese accessions Yumai 10 and Yu 02321 showed moderate to high levels of blast resistance,accounting for only 3.8%in the panel.Fifty-eight significant SNPs clustered in a 28.9 Mb interval on the 2 AS/2 NS translocation region,explaining phenotypic variation between10.0%and 35.0%.The frequency of the 2 AS/2 NS translocation in the Chinese accessions was as low as4.5%.These results indicated that the 2 NS fragment was the only major locus conferring resistance to wheat blast in this panel,and the resistant and moderately resistant lines identified could be deployed in breeding.