The psyllid fauna (Hemiptera: Psylloidea) of vegetable fields in Brazil

ABSTRACT Some psyllids transmit 'Candidatus Liberibacter solanacearum' (Lso), the causal agent of devastating plant diseases of cultivated Solanaceae and Apiaceae. The recent detection of Bactericera cockerelli and Lso in Ecuador seriously threatens these crops in South America. There, neither the role of native psyllids in the Lso epidemiology nor the psyllid fauna of vegetables are known. With the aim to identify potential vectors and risk scenarios for the spread of Lso in South America, a survey of the psyllid fauna of Solanaceae and Apiaceae crops and associated weeds was conducted in Brazil. Samples were taken at 29 localities in four states. A total of 2857 specimens were sampled, representing at least 37 species of 23 genera and seven families. The most frequent species on carrot, chilli pepper and potato were Russelliana solanicola, R. capsici and Isogonoceraia divergipennis, respectively. Immatures of R. capsici were found on chilli pepper and of R. solanicola on carrot and potato, confirming these plants as hosts. The two psyllid species have been suspected previously to transmit plant pathogens of unknown identity. Russelliana solanicola is one of the few polyphagous species. Here the species is reported for the first time from carrot. Recent collections in Rio Grande do Sul suggest that Solanum laxum represents the original host of R. capsici, which subsequently shifted to chilli pepper. Both, adaptation to agricultural crops and the possibility of ability to transmit pathogens, make the two Russelliana species dangerous potential vectors of Lso and other plant pathogens in South America.

Evaluation of the Chilli veinal mottle virus CP gene expressing transgenic Nicotiana benthamiana plants for disease resistance against the virus / Avaliação do gene CP do vírus Chilli veinal mottle que expressa plantas transgênicas Nicotiana benthamiana quanto à resistência a doenças contra o vírus

Vegetables are an important source of income and high-value crops for small farmers. Chilli (Capsicum spp.) is one of the most economically important vegetables of Pakistan and it is grown throughout the country. It is a rich source of nutrition especially vitamins A, B, C and E along with minerals as folic acid, manganese (Mn), potassium (K) and molybdenum (Mo). Chilli possesses seven times more amount of vitamin C than an orange. Vitamin A, C and beta carotenoids are strong antioxidants to scavenge the free radicals. Chilli production is restricted due to various biotic factors. Among these viruses, Chilli veinal mottle virus (ChiVMV) is one of the most destructive and menacing agents that inflicts heavy and colossal losses that accounted for 50% yield loss both in quality and quantity. Pathogen-Derived Resistance (PDR) approach is considered one of the effective approaches to manage plant viruses. In this study, ChiVMV was characterized on a molecular level, the coat protein (CP) gene of the virus was stably transformed into Nicotiana benthamiana plants using Agrobacterium tumefaciens. The transgenic plants were challenged with the virus to evaluate the level of resistance of plants against the virus. It was observed that the plants expressing CP gene have partial resistance against the virus in terms of symptoms' development and virus accumulation. Translation of this technique into elite chilli varieties will be resulted to mitigate the ChiVMV in the crop as well as an economic benefit to the farmers.

Vegetais são uma importante fonte de renda e culturas de alto valor para os pequenos agricultores. A pimenta-malagueta (Capsicum spp.) é uma das hortaliças mais importantes economicamente do Paquistão e é cultivada em todo o país. É uma rica fonte de nutrição, especialmente vitaminas A, B, C e E com minerais como ácido fólico, manganês (Mn), potássio (K) e molibdênio (Mo). O pimentão possui sete vezes mais vitamina C do que a laranja. Vitaminas A e C e betacarotenoides são antioxidantes fortes para eliminar os radicais livres. A produção de pimenta é restrita devido a vários fatores bióticos. Entre esses vírus, o ChiVMV é o agente mais destrutivo e ameaçador que inflige perdas pesadas e colossais que representam 50% da perda de rendimento, tanto em qualidade quanto em quantidade. A abordagem de resistência derivada de patógenos (PDR) é considerada uma das abordagens eficazes para gerenciar os vírus de plantas. Neste estudo, ChiVMV foi caracterizado em nível molecular e o gene CP do vírus foi transformado de forma estável em plantas Nicotiana benthamiana usando Agrobacterium tumefaciens. As plantas transgênicas foram desafiadas com o vírus para avaliar seu nível de resistência contra o vírus. Observou-se que as plantas que expressam o gene CP apresentam resistência parcial ao vírus em termos de desenvolvimento de sintomas e acúmulo de vírus. A tradução dessa técnica em variedades de pimenta de elite resultará na mitigação do ChiVMV na safra, bem como em benefícios econômicos para os agricultores em termos de melhor rendimento e baixo custo de produção.

Evaluation of the Chilli veinal mottle virus CP gene expressing transgenic Nicotiana benthamiana plants for disease resistance against the virus

Abstract Vegetables are an important source of income and high-value crops for small farmers. Chilli (Capsicum spp.) is one of the most economically important vegetables of Pakistan and it is grown throughout the country. It is a rich source of nutrition especially vitamins A, B, C and E along with minerals as folic acid, manganese (Mn), potassium (K) and molybdenum (Mo). Chilli possesses seven times more amount of vitamin C than an orange. Vitamin A, C and beta-carotenoids are strong antioxidants to scavenge the free radicals. Chilli production is restricted due to various biotic factors. Among these viruses, Chilli veinal mottle virus (ChiVMV) is one of the most destructive and menacing agents that inflicts heavy and colossal losses that accounted for 50% yield loss both in quality and quantity. Pathogen-Derived Resistance (PDR) approach is considered one of the effective approaches to manage plant viruses. In this study, ChiVMV was characterized on a molecular level, the coat protein (CP) gene of the virus was stably transformed into Nicotiana benthamiana plants using Agrobacterium tumefaciens. The transgenic plants were challenged with the virus to evaluate the level of resistance of plants against the virus. It was observed that the plants expressing CP gene have partial resistance against the virus in terms of symptoms development and virus accumulation. Translation of this technique into elite chilli varieties will be resulted to mitigate the ChiVMV in the crop as well as an economic benefit to the farmers.

Resumo Vegetais são uma importante fonte de renda e culturas de alto valor para os pequenos agricultores. A pimenta-malagueta (Capsicum spp.) é uma das hortaliças mais importantes economicamente do Paquistão e é cultivada em todo o país. É uma rica fonte de nutrição, especialmente vitaminas A, B, C e E com minerais como ácido fólico, manganês (Mn), potássio (K) e molibdênio (Mo). O pimentão possui sete vezes mais vitamina C do que a laranja. Vitaminas A e C e betacarotenoides são antioxidantes fortes para eliminar os radicais livres. A produção de pimenta é restrita devido a vários fatores bióticos. Entre esses vírus, o ChiVMV é o agente mais destrutivo e ameaçador que inflige perdas pesadas e colossais que representam 50% da perda de rendimento, tanto em qualidade quanto em quantidade. A abordagem de resistência derivada de patógenos (PDR) é considerada uma das abordagens eficazes para gerenciar os vírus de plantas. Neste estudo, ChiVMV foi caracterizado em nível molecular e o gene CP do vírus foi transformado de forma estável em plantas Nicotiana benthamiana usando Agrobacterium tumefaciens. As plantas transgênicas foram desafiadas com o vírus para avaliar seu nível de resistência contra o vírus. Observou-se que as plantas que expressam o gene CP apresentam resistência parcial ao vírus em termos de desenvolvimento de sintomas e acúmulo de vírus. A tradução dessa técnica em variedades de pimenta de elite resultará na mitigação do ChiVMV na safra, bem como em benefícios econômicos para os agricultores em termos de melhor rendimento e baixo custo de produção.

Evaluation of the Chilli veinal mottle virus CP gene expressing transgenic Nicotiana benthamiana plants for disease resistance against the virus / Avaliação do gene CP do vírus Chilli veinal mottle que expressa plantas transgênicas Nicotiana benthamiana quanto à resistência a doenças contra o vírus

Vegetables are an important source of income and high-value crops for small farmers. Chilli (Capsicum spp.) is one of the most economically important vegetables of Pakistan and it is grown throughout the country. It is a rich source of nutrition especially vitamins A, B, C and E along with minerals as folic acid, manganese (Mn), potassium (K) and molybdenum (Mo). Chilli possesses seven times more amount of vitamin C than an orange. Vitamin A, C and betacarotenoids are strong antioxidants to scavenge the free radicals. Chilli production is restricted due to various biotic factors. Among these viruses, Chilli veinal mottle virus (ChiVMV) is one of the most destructive and menacing agents that inflicts heavy and colossal losses that accounted for 50% yield loss both in quality and quantity. Pathogen-Derived Resistance (PDR) approach is considered one of the effective approaches to manage plant viruses. In this study, ChiVMV was characterized on a molecular level, the coat protein (CP) gene of the virus was stably transformed into Nicotiana benthamiana plants using Agrobacterium tumefaciens. The transgenic plants were challenged with the virus to evaluate the level of resistance of plants against the virus. It was observed that the plants expressing CP gene have partial resistance against the virus in terms of symptoms' development and virus accumulation. Translation of this technique into elite chilli varieties will be resulted to mitigate the ChiVMV in the crop as well as an economic benefit to the farmers.

Vegetais são uma importante fonte de renda e culturas de alto valor para os pequenos agricultores. A pimenta-malagueta (Capsicum spp.) é uma das hortaliças mais importantes economicamente do Paquistão e é cultivada em todo o país. É uma rica fonte de nutrição, especialmente vitaminas A, B, C e E com minerais como ácido fólico, manganês (Mn), potássio (K) e molibdênio (Mo). O pimentão possui sete vezes mais vitamina C do que a laranja. Vitaminas A e C e betacarotenoides são antioxidantes fortes para eliminar os radicais livres. A produção de pimenta é restrita devido a vários fatores bióticos. Entre esses vírus, o ChiVMV é o agente mais destrutivo e ameaçador que inflige perdas pesadas e colossais que representam 50% da perda de rendimento, tanto em qualidade quanto em quantidade. A abordagem de resistência derivada de patógenos (PDR) é considerada uma das abordagens eficazes para gerenciar os vírus de plantas. Neste estudo, ChiVMV foi caracterizado em nível molecular e o gene CP do vírus foi transformado de forma estável em plantas Nicotiana benthamiana usando Agrobacterium tumefaciens. As plantas transgênicas foram desafiadas com o vírus para avaliar seu nível de resistência contra o vírus. Observou-se que as plantas que expressam o gene CP apresentam resistência parcial ao vírus em termos de desenvolvimento de sintomas e acúmulo de vírus. A tradução dessa técnica em variedades de pimenta de elite resultará na mitigação do ChiVMV na safra, bem como em benefícios econômicos para os agricultores em termos de melhor rendimento e baixo custo de produção.

Effectiveness of indigenous fluorescent pseudomonads in suppressing Rhizoctonia solani root rot disease and promoting plant growth in chilli seedlings

Aims@#This study aimed to isolate and evaluate the indigenous fluorescent Pseudomonas spp. with bio-control potential against Rhizoctonia solani and promoting growth in chilli seedlings. @*Methodology@#A total of 120 fluorescent bacterial were isolated from the healthy chilli rhizosphere soil from the seven major chilli cultivation localities in Terengganu, Malaysia. Only 115 Gram negative fluorescent isolates were further invitro screened for antagonistic activities against R. solani and plant growth-promoting properties. The 50 most effective fluorescent Pseudomonads antagonist against R. solani with minimum percentage inhibition of radial growth (PIRG) of 65% were selected. Hierarchical cluster analysis was further conducted with two dendrograms derived from SPSS Statistic 20 to facilitate the comparison between these 50 isolates for antagonistic and growth-promoting properties. A total of 40 fluorescent isolates within the most potential cluster were further selected and identified using 16S rRNA sequencing. Thirty four fluorescent isolates were identified as Pseudomonas spp. and six isolates as Burkholderia spp. The top 13 ranked fluorescent Pseudomonas spp. from the scoring index were evaluated for seed germination and vigor index in chilli seedlings. There was no significant difference in germination rate between fluorescent Pseudomonas inoculated with control. However, vigor index of chilli seeds pre-inoculated with fluorescent P. putida (B5C1), P. aeruginosa (B3C56) and P. putida (B5C7) were significantly increased with 4684.9, 4657.3 and 4401.0 over control (P ≤ 0.05).@*Conclusion, significance and impact of study@#These selected fluorescent isolates: P. putida (B5C1), P. aeruginosa (B3C56) and P. putida (B5C7) have the potential to be developed as biofungicide against R. solani and as growthpromoter in chilli production system.

Colletotrichum spp. associated with agricultural crops in Malaysia, causal pathogens and potential control methods

ABSTRACT@#Colletotrichum is one of the most significant and common plant pathogens, infecting many economically important crops worldwide. Colletotrichum is also one of the most studied fungal genera in Malaysia because it contains many species that infect various types of agricultural crop including fruit, vegetable and industrial crops. Studies on Colletotrichum spp. are mostly focused on the causal pathogens, the host range and disease management. Among the host crops, most studies on Colletotrichum spp. have been conducted on infection in chilli (Capsicum spp.), which, in Malaysia, first arose in the 1980s and still continues to be a problem to this day. Studies have also been conducted on Colletotrichum spp. associated with anthracnose in fruit crops including dragon fruit, papaya, banana and mango. Disease management of anthracnose pathogens postharvest has also been conducted to prolong the shelf life of these fruit crops. In this review, Colletotrichum spp. associated with chilli and several fruit crops as well as their disease management are highlighted. There have been many changes in Colletotrichum taxonomy and systematics in recent years, affecting the identification of anthracnose pathogens reported in Malaysia. Colletotrichum species identified solely by morphology or solely via the internal transcribed spacer (ITS) region should be referred to as sensu lato (in the broad sense) since many species belong to species complexes. Species within a species complex are closely related, and most are cryptic species particularly species in the C. gloeosporioides and C. acutatum complexes which are commonly associated with agricultural crops in Malaysia. Due to the importance of Colletotrichum spp. as plant pathogens, up-to-date identification methods should be used since accurate species identification of Colletotrichum is crucial for formulating suitable disease management programmes as well as for plant quarantine and biosecurity purposes. This review provides the current knowledge on the status of Colletotrichum spp. associated with agricultural crops in Malaysia and potential control methods on different types of agricultural crops.

Developing novel bacterial based bioformulation having PGPR properties for enhanced production of agricultural crops.

Plant growth promoting rhizobacteria (PGPR) are beneficial rhizobacteria which enhance plant growth as well as the productivity by a variety of mechanisms. PGPR were isolated from the rhizosphere region of som plants (Machilus bombycina King) maintained at the Central Muga Eri Research and Training Institute, Lahdoigarh, Jorhat. A bacterial based bioformulation was prepared and sprayed over the experimental crops including tomato (Solanum lycopersicum), cauliflower (Brassica oleracea var botrytis), chili (Capsicum annuum) and brinjal (Solanum melongena). Biochemical analysis was done on these PGPR treated crops as well as the untreated crops. The bioformulations prepared from Bacillus cereus (MTCC 8297), Pseudomonas rhodesiae (MTCC 8299) and Pseudomonas rhodesiae (MTCC 8300) was found to be the most effective in increasing the shoot height, number of leaves, early fruiting and total biomass content of the plants after treatment.

Effect of plastic mulch on growth and yield of chilli (Capsicum annuum L.)

In this work a field study was conducted to evaluate the effect of coloured plastic mulch on growth and yield of chilli from October 2005 to April 2006. The plastic mulches were transparent, blue, and black and bare soil was the control. Different mulches generated higher soil temperature and soil moisture under mulch over the control. Transparent and blue plastic mulches encouraged weed population which were suppressed under black plastic. Plant height, number of primary branches, stem base diameter, number of leaves and yield were better for the plants on plastic. At the mature green stage, fruits had the highest vitamin-C content on the black plastic. Mulching produced the fruits with the highest chlorophyll-a, chlorophyll-b and total chlorophyll contents and also increased the number of fruits per plant and yield. However, mulching did not affect the length and diameter of the fruits and number of seeds per fruit. Plants on black plastic mulch had the maximum number of fruits and highest yield. Thus, mulching appears to be a viable tool to increase the chilli production under tropical conditions.

Polygalacturonase inhibitor protein from fruits of anthracnose resistant and susceptible varieties of Chilli (Capsicum annuum L).

Chilli fruit is highly susceptible to anthracnose infection at the stage of harvest maturity, due to which the fruit yield in the leading commercial variety Byadgi is severely affected. Field studies on screening of several varieties for resistance to anthracnose have shown that a variety of chilli AR-4/99K is resistant to anthracnose infection. In many crops, resistance to fungal attack has been correlated with PGIP activity in developing fruits based on which transgenic varieties have been developed with resistance to fungi. The present study was carried out to determine whether anthracnose resistance in AR-4/99K was due to the increased levels of PGIP alone and/ or due to differences, if any, in the properties of PGIP. Hence, a comparative study of the properties of polygalacturonase inhibitor protein (PGIP) isolated from fruits of anthracnose resistant chilli var AR-4/99K and a susceptible variety Byadgi was conducted with the objective of utilizing the information in genetic transformation studies. Both the PGIPs from anthracnose resistant and susceptible varieties of chilli exhibited similarities in the elution pattern on Sephadex gel, DEAE cellulose, PAGE and SDS-PAGE. The two PGIPs were active over a wide range of pH and temperature. Both PGIPs showed differential inhibitory activity against polygalacturonase (PG) secreted by Colletotrichum gleosporoides, C. capsici, C. lindemuthianum, Fusarium moniliforme and Sclerotium rolfsii. The inhibitory activity of PGIP from both resistant and susceptible varieties was the highest (82% and 76%, respectively) against the PG from Colletotrichum capsici, a pathogen causing anthracnose rot of chilli, while the activity was lower (1.27 to 12.3%) on the other fungal PGs. Although PGIP activity decreased with fruit maturation in both the varieties, the resistant variety maintained a higher activity at 45 days after flowering (DAF) as compared to the susceptible variety which helped it to overcome the infection by anthracnose as against the susceptible variety (Byadgi) in which PGIP activity was drastically reduced at maturity. The molecular mass of PGIP as determined by SDS-PAGE was found to be 37 kDa. N-terminal sequence analysis of the PGIP showed the first six amino acid residues from N-terminal end were Asp-Thr-His-Lys-Ser-Glu (DTHKSE), respectively. The similarities in properties of the two PGIPs support the earlier findings that resistance of AR-4/99K to anthracnose fungus is a result of its higher PGIP activity at maturity.