Management of potato virus Y (PVY) in potato by some biocontrol agents under field conditions

. Management of potato virus Y (PVY) in potato by some biocontrol agents under field conditions. International Journal of Agricultural Technology 9(4):855-861. Abstract The study was conducted to test the activity of Pseudomonas fluorescens, Rhodotorula sp and fermented neem extract to protect potato plants against potato virusY disease development under field conditions. Infected potato tubers were soaked in P. fluorescens , Rhodotorula sp suspensions and in fermented neem extracts separately and sown in the field in completely randomized block design. The development of virus symptoms and the accumulation of virus in the plant based on Enzyme Linked Immunosorbent Assay (ELISA) were noted. The results obtained showed that the treatment of potato tubers with the three agents have significantly accelerated plant emergence, 5-6 days earlier than non treated ones, and improved plant growth. The plant dry weights ranged from 120-177 g/plant compared to 42 g/plant in non treated plants. The enhancement of plant growth was found to be associated with reduction in disease severity based on symptoms development and restriction of virus concentration as proven by ELISA absorbance of 405 nm, 0.14-0.23 compared with 2.50 in non treated plants. The results indicated that the use of bio-agent to induce systemic resistance provide an efficient tool, as insecticide alternative to manage potato virus Y in potato

The wheat Sr22, Sr33, Sr35 and Sr45 genes confer resistance against stem rust in barley

In the last 20 years, stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt), has re-emerged as a major threat to wheat and barley production in Africa and Europe. In contrast to wheat with 60 designated stem rust (Sr) resistance genes, barley’s genetic variation for stem rust resistance is very narrow with only ten resistance genes genetically identified. Of these, only one complex locus consisting of three genes is effective against TTKSK, a widely virulent Pgt race of the Ug99 tribe which emerged in Uganda in 1999 and has since spread to much of East Africa and parts of the Middle East. The objective of this study was to assess the functionality, in barley, of cloned wheat Sr genes effective against race TTKSK. Sr22, Sr33, Sr35 and Sr45 were transformed into barley cv. Golden Promise using Agrobacterium-mediated transformation. All four genes were found to confer effective stem rust resistance. The barley transgenics remained susceptible to the barley leaf rust pathogen Puccinia hordei, indicating that the resistance conferred by these wheat Sr genes was specific for Pgt. Furthermore, these transgenic plants did not display significant adverse agronomic effects in the absence of disease. Cloned Sr genes from wheat are therefore a potential source of resistance against wheat stem rust in barley

Screening of Mycotoxin Produced by Fusarium Verticillioides and F. Proliferatum in Culture Media

This study was conducted to evaluate the production of mycotoxin by Fusarium verticillioides and Fusarium proliferatum strain in culture media. Results of Fusarium strain speciation by sequencing technique for the αTEF gene regent showed that 16 isolates from 21 belong to F. verticelloides, four to F. proliferatum and one to Fusarium solani. Mycotoxin production test showed that all Fusarium strains obtained produce different levels of T2-toxin, DON, ZEN and fumonisin in culture media with fumonisin toxin having the highest chemotype produced

ORIGINAL ARTICLE Management of potato virus Y (PVY) in potato by some biocontrol agents under field conditions

ABSTRACT The study was conducted to test the activity of Pseudomonas fluorescens, Rhodotorula sp and fermented neem extract to protect potato plants against potato virusY disease development under field conditions. Infected potato tubers were soaked in P. fluorescens , Rhodotorula sp suspensions and in fermented neem extracts separately and sown in the field in completely randomized block design. The development of virus symptoms and the accumulation of virus in the plant based on Enzyme Linked Immunosorbent Assay (ELISA) were followed. The results obtained showed that the treatment of potato tubers with the three agents have significantly accelerated plant emergence, 5-6 days early than non treated ones, and improved plant growth , the plant dry weights ranged from 120-177 g/plant compared to 42 g/plant in non treated plants. The enhancement of plant growth was found associated with reduction in disease severity based on symptoms development and restriction of virus concentration as proved by ELISA absorbance of 405 nm, 0.14-0.23 compared with 2.50 in non treated plants. The results indicated that the use of bioagent to induce systemic resistance provide an efficient tool, as insecticide alternative to manage potato virus Y in potato

Geographic distribution of Fusarium culmorum chemotypes associated with wheat crown rot in Iraq

Fusarium crown rot (FCR) is an important disease of wheat and other grains that has had a significant impact on cereal crop production worldwide. Fusarium species associated with FCR can also produce powerful trichothecenes mycotoxins that pose a considerable health risk to humans and animals that consume infected grains. In this study we examined Fusarium species of wheat from different regions of Iraq that showed FCR symptoms. Twenty-nine isolates were collected overall, and the marker gene translation elongation factor 1 alpha (TEF-1α) was sequenced in order to determine their taxonomic identities. All isolates were determined to be F. culmorum, and primers targeting tri-cluster genes were used in order to further characterize isolates into specific trichothecene chemotype strains. Five of the 29 isolates were determined to be the nivalenol (NIV) chemotype, while the rest of the isolates recovered were the deoxynivalenol (DON) chemotype. All DON- -type isolates produced 3Ac-DON, while the 15Ac-DON-type was not detected. The majority of the NIV-type isolates originated from wheat growing regions in the mid-latitudes of Iraq, while the DON-type isolates were recovered from areas distributed broadly across the country. To the best of our knowledge, this study is the first to report on the distribution of specific F. culmorum chemotypes from FCR diseased wheat in Iraq

Original Article. Geographic distribution of Fusarium culmorum chemotypes associated with wheat crown rot in Iraq

Fusarium crown rot (FCR) is an important disease of wheat and other grains that has had a significant impact on cereal crop production worldwide. Fusarium species associated with FCR can also produce powerful trichothecenes mycotoxins that pose a considerable health risk to humans and animals that consume infected grains. In this study we examined Fusarium species of wheat from different regions of Iraq that showed FCR symptoms. Twenty-nine isolates were collected overall, and the marker gene translation elongation factor 1 alpha (TEF-1α) was sequenced in order to determine their taxonomic identities. All isolates were determined to be F. culmorum, and primers targeting tri-cluster genes were used in order to further characterize isolates into specific trichothecene chemotype strains. Five of the 29 isolates were determined to be the nivalenol (NIV) chemotype, while the rest of the isolates recovered were the deoxynivalenol (DON) chemotype. All DON- -type isolates produced 3Ac-DON, while the 15Ac-DON-type was not detected. The majority of the NIV-type isolates originated from wheat growing regions in the mid-latitudes of Iraq, while the DON-type isolates were recovered from areas distributed broadly across the country. To the best of our knowledge, this study is the first to report on the distribution of specific F. culmorum chemotypes from FCR diseased wheat in Iraq

Management of potato virus Y (PVY) in potato by some biocontrol agents under field conditions

<p>The study was conducted to test the activity of Pseudomonas fluorescens, Rhodotorula sp and<br>fermented neem extract to protect potato plants against potato virusY disease development under field conditions. Infected potato tubers were soaked in P. fluorescens, Rhodotorula sp suspensions and in fermented neem extracts separately and sown in the field in completely randomized block design. The<br>development of virus symptoms and the accumulation of virus in the plant based on Enzyme Linked Immunosorbent Assay (ELISA) were followed. The results obtained showed that the treatment of potato tubers with the three agents have significantly accelerated plant emergence, 5-6 days early than non treated ones, and improved plant growth, the plant dry weights ranged from 120-177 g/plant compared to 42 g/plant in non treated plants. The enhancement of plant growth was found associated with reduction in disease severity based on symptoms development and restriction of virus<br>concentration as proved by ELISA absorbance of 405 nm, 0.14-0.23 compared with 2.50 in non treated plants. The results indicated that the use of bioagent to induce systemic resistance provide an efficient tool, as insecticide alternative to manage potato virus Y in potato.</p

Host range expansion of wheat stem rust resistance genes into barley

In the last 20 years, stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt), has re-emerged as a major threat to wheat and barley cultivation in Africa and Europe. In contrast to wheat with 82 designated stem rust (Sr) resistance genes, barley’s genetic variation for stem rust resistance is very narrow with only seven resistance genes genetically identified. Of these, only one locus consisting of two genes is effective against Ug99, a strain of Pgt which emerged in Uganda in 1999 and has since spread to much of East Africa and parts of the Middle East. The objective of this study was to assess the functionality, in barley, of cloned wheat Sr genes effective against Ug99. Sr22, Sr33, Sr35 and Sr45 were transformed into barley cv. Golden Promise using Agrobacterium-mediated transformation. All four genes were found to confer effective stem rust resistance. The barley transgenics remained susceptible to the barley leaf rust pathogen Puccinia hordei, indicating that the resistance conferred by these wheat Sr genes was specific for Pgt. Cloned Sr genes from wheat are therefore a potential source of resistance against wheat stem rust in barley

Population genomic analysis of Aegilops tauschii identifies targets for bread wheat improvement.

Aegilops tauschii, the diploid wild progenitor of the D subgenome of bread wheat, is a reservoir of genetic diversity for improving bread wheat performance and environmental resilience. Here we sequenced 242 Ae. tauschii accessions and compared them to the wheat D subgenome to characterize genomic diversity. We found that a rare lineage of Ae. tauschii geographically restricted to present-day Georgia contributed to the wheat D subgenome in the independent hybridizations that gave rise to modern bread wheat. Through k-mer-based association mapping, we identified discrete genomic regions with candidate genes for disease and pest resistance and demonstrated their functional transfer into wheat by transgenesis and wide crossing, including the generation of a library of hexaploids incorporating diverse Ae. tauschii genomes. Exploiting the genomic diversity of the Ae. tauschii ancestral diploid genome permits rapid trait discovery and functional genetic validation in a hexaploid background amenable to breeding

Population genomic analysis of Aegilops tauschii identifies targets for bread wheat improvement

Aegilops tauschii, the diploid wild progenitor of the D subgenome of bread wheat, is a reservoir of genetic diversity for improving bread wheat performance and environmental resilience. Here we sequenced 242 Ae. tauschii accessions and compared them to the wheat D subgenome to characterize genomic diversity. We found that a rare lineage of Ae. tauschii geographically restricted to present-day Georgia contributed to the wheat D subgenome in the independent hybridizations that gave rise to modern bread wheat. Through k-mer-based association mapping, we identified discrete genomic regions with candidate genes for disease and pest resistance and demonstrated their functional transfer into wheat by transgenesis and wide crossing, including the generation of a library of hexaploids incorporating diverse Ae. tauschii genomes. Exploiting the genomic diversity of the Ae. tauschii ancestral diploid genome permits rapid trait discovery and functional genetic validation in a hexaploid background amenable to breeding