The Mechanisms of Trichoderma Species to Reduce Drought and Salinity Stress in Plants

Environmental stresses caused by climate change have severely affected agriculture in the present century;Salinity and drought have challenged most forecasts for increased agricultural production in the past few decades,there-fore,different methods that reduce the effect of these stresses on plants have attracted scientists’attention.The effect of beneficial soil microorganisms on soil health and increasing plants’resistance to stresses is one of the solutions that researchers have paid attention to.This study investigated how Trichoderma species can be affected by the molecular and morphophysiological mechanisms of plants and improve their salt and drought resistance.This study also studied the different Trichoderma species’functions to get a better understanding of how they reduce salt and drought stresses.Furthermore,thefindings of this study provide a clear path for future research to focus on the unknown aspects of Trichoderma species andfind effective ways to boost crop production under environmental stresses.

Characterization and screening of cotton(Gossypium hirsutum L.)germplasm for leafhopper(Amrasca biguttula biguttula(Ishida))resistance

Background Cotton(Gossypium hirsutum L.)is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies.However,over the years quantity and quality have been hampered by the pest leafhopper.Leafhopper alone has been shown to cause yield losses of up to 40%.In this study,screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant,moderately resistant,sensitive and highly sensitive to leafhoppers.Results A total of hundred genotypes were evaluated along with five checks for leafhopper resistance.Based on the screening results,a total of 19 genotypes were resistant to leafhoppers,which was on par with the findings of the check KC 3.The contents of total soluble sugar,total soluble protein,and total free amino acids were significantly positively correlated with the mean grade,whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade.However,based on screening and biochemical analysis,the genotypes KC 2,JR-23,Samaru-26-T,D 4,TCH 1728,RS 253,and B-61-1862 exhibited high resistance to leafhopper.Conclusion According to the findings of this study,choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar,total soluble protein,and free amino acids may aid in the development of resistant genotypes.

Release of Stem Rust Resistant Wheat Varieties for Commercial Production in Kenya

Detection in 1999 of a new stem rust （Puccinia graminis f. sp. tritici） race Ug99 in Uganda with broad virulence including the virulence for Sr31 and its migration to Kenya and Ethiopia has been recognized as a significant threat to local and world wheat production. All the Current Kenyan commercial varieties are susceptible to this race. This study was aimed at identifying suitable wheat varieties with resistance to Ug99 and replacing the susceptible commercial varieties through multi-locational testing and variety release. Thirty three lines were identified from a prescreen population of 104 lines and tested in 3 wheat growing regions in Kenya for two seasons in 2006 and 2007. The resulting four superior lines were evaluated under the National Performance Trial （NPT） where two lines which out-performed the best check variety were released as for commercial production. ＇Robin＇ was the best line and out yielded the commercial variety by 27%. ＂Eaglel0＂ was the second best and was better significantly than the check variety. These two lines which combined both adult plant resistant gene Sr2 complex and other major genes are expected to have some durable resistance and may be used to replace the current susceptible commercial varieties grown in Kenya.

Application of Real-time Fluorescent Quantitative PCR in Plant

Real-time fluorescent quantitative PCR （RQ-PCR） is a detection method by adding fluorescent dye or fluorescent probe into the PCR reaction system, using fluorescent signal accumulation to monitor amplification reactions of PCR reaction process, and finally the unknown template can be quantitatively analyzed through the standard curve. So the detection level of PCR has improved from the qualitative to the quantitative. In order to provide a theoretical reference for further application, the principle, classification, advantages and disadvantages of RQ-PCR were intro- duced, and its application and progress in plants in recent years were reviewed.

Advances on Rare Earth Application in Pollution Ecology

The use of rare earth for inducing plant resistance was reviewed. The important developments in recent years were described, and rare earth can alleviate the pollution of acid rain, ozone, pesticide, heavy metals etc. in environment. The authors suggest that the mechanism of rare earth to inducing plant resistance and reducing plant injury is to control biochemical metabolism web in plant cell, to adjust its protection system of free radical, to maintain its photosynthesis, to protect cell membrane system and to carry through its function on mineral metabolism. Meanwhile some problems in the field were discussed as well.

Effects of silicon amendment on the occurrence of rice insect pests and diseases in a field test

Rice is one of the most important staple foods for the world population,but it is attacked by a number of destructive pests.While evidence from greenhouse and laboratory tests has shown that silicon（Si）amendment can confer enhanced resistance to pests in rice,few studies have directly demonstrated the Si-mediated protection from pests in a field situation.In this study,field plots with silicon amendments at 0,75,150 and 300 kg SiO2 ha-1 in early-and late-season rice were employed to evaluate the effects of silicon amendment on the occurrence of major insect pests and diseases and rice yield.Compared with the control plots without silicon amendment,plant damage by stem borer and leaf folder and population size of planthopper were significantly lower in three to five of the seven monitoring observations in each season in the plots amended with 300 kg SiO2 ha-1.The disease index of rice blast in the early-season rice was lower in the plots amended with Si at 300 kg SiO2 ha-1 than in the control plots,while Si protection from rice blast in the late-season rice and from rice sheath blight in the early-season rice were not apparent.An insignificant increase of rice yield by 16.4%（604 kg ha-1）was observed in the plots amended with 300 kg SiO2 ha-1 over the control plots.Our results indicate that Si amendment at 300kg SiO2 ha-1 can provide substantial protection from some of the rice pests under field conditions.These findings support the recommendation of silicon amendment as a key component of integrated management of rice pests.

Evaluation of the Resistance of Different Tea Cultivars to Tea Aphids by EPG Technique

In order to investigate the resistance of tea plant to tea aphid, the feeding behavior of tea aphids on six different tea cultivars was monitored by （EPG） technique. The result showed that the duration of El, E2 as well as （E I＋E2） which was feeding waveforrns of Toxoptera aurantii （Boyer） in tea phloem was significantly different by variance analysis （P〈0.05） and so did the duration of the probing of T. aurantii in all the tea tissues. And the six tea cultivars were classified into three groups with cluster analysis, based on the six major parameters which were durations of np, C, El, E2, F, and G waveforms, then the six major parameters of these three groups were detected by variance analysis, and the rank of six different tea cultivars＇ resistance to T. aurantii from strong to weak was Zhongcha 108, Sucha 1, Anjibaicha, Longjing 43, Xicha 5, and Sucha 120. As this result was in accord with the investigation into the tea field, we concluded that EPG technique was one of the most important means to examine tea plant resistance to T. aurantii and the durations of waveform El, E2 and （El＋E2） were important parameters for evaluating resistance of tea plants to tea aphids.

Field Evaluation of the Asian Corn Borer Control in Hybrid of Transgenic Maize Event MON 810

In this study, a transgenic Bt maize hybrid (event MON 810 from Monsanto Company) expressing Cry1Ab protein derived from Bacillus thuringiensis (Bt) and its negative isoline hybrid were evaluated for control of the Asian corn borer, Ostrinia furnacalis (Guenée) (Lepidoptera: Pyralidae), in a field trial. Maize plants were artificially infested with neonate larvae of Asian corn borer at the mid-whorl (first-generation), pre-tassel (first- and/or second-generation), and silk (second-generation) growth stages. The transgenic Bt maize hybrid sustained significantly less leaf feeding damage (rating 1.0±0.0) than its negative isoline control (rating 7.3±0.1). With the Bt maize, 1.36.8% of plants were damaged by corn borer tunneling with <0.5 cm tunneling per stalk under different levels of infestation, compared with 100% of plants damaged with 9.325.0 cm tunneling per stalk for the negative isoline control. On average, transgenic Bt maize hybrids had only 0.010.05 tunnels per stalk and no stems were broken. In contrast, the negative isoline control had 3.118.36 tunnels per stalk and 31.273.9% of stems broken. Yields were significantly higher in transgenic Bt maize than in the control. These results demonstrate that transgenic Bt maize can significantly minimize yield losses caused by the Asian corn borer through resistance to the first- and second-generation larvae.

Pathogenesis-related protein genes involved in race-specific allstage resistance and non-race specific high-temperature adultplant resistance to Puccinia striiformis f. sp. tritici in wheat

Interactions of the stripe rust pathogen （Puccinia striiformis f. sp responses. Among various genes involved in the plant-pathogen related （PR） protein genes determine different defense responses tritici） with wheat plants activate a w^ae range OT nost nteractions, the expressions of particular pathogenesis-Different types of resistance have been recognized and utilized for developing wheat cultivars for resistance to stripe rust. All-stage resistance can be detected in seedling stage and remains at high levels throughout the plant growth stages. This type of resistance is race-specific and not durable. In contrast, plants with only high-temperature adult-plant （HTAP） resistance are susceptible in seedling stage, but become resistant when plants grow older and the weather becomes warmer. HTAP resistance controlled by a single gene is partial, but usually non-race specific and durable. The objective of this study was to analyze the expression of PR protein genes involved in different types of wheat resistance to stripe rust. The expression levels of 8 PR protein genes （PR1, PRI.2, PR2, PR3, PR4, PR5, PR9 and PRIO） were quantitatively evaluated at 0, 1, 2, 7 and 14 days after inoculation in single resistance gene lines of wheat with all-stage resistance genes YrTrl, Yr76, YrSP and YrExp2 and lines carrying HTAP resistance genes Yr52, Yr59, Yr62 and Yr7B. Races PSTv-4 and PSTv-37 for compatible and incompatible interactions were used in evaluation of PR protein gene expression in wheat lines carrying all-stage resistance genes in the seedling- stage experiment while PSTv-37 was used in the HTAP experiment. Analysis of quantitative real-time polymerase chain reaction （qRT-PCR） revealed that all of the PR protein genes were involved in the different types of resistance controlled by different Yr genes. However, these genes were upregulated at different time points and at different levels during the infection process among the wheat lines with different Yr genes for either all-stage resistance or HTAP resistance. Some of the genes were also induced in compatible interactions, but the levels were almost always higher in the incompatible interaction than in the compatible interaction at the same time point for each Yr gene. These results indicate that both salicylic acid and jasmonate signaling pathways are involved in both race-specific all-stage resistance and non-race specific HTAP resistance. Although expressing at different stages of infection and at different levels, these PR protein genes work in concert for contribution to different types of resistance controlled by different Yr genes.

NaPDR1 and NaPDR1-like are essential for the resistance of Nicotiana attenuata against fungal pathogen Alternaria alternata

Pleiotropic drug resistance(PDR) transporters are widely distributed membrane proteins catalyzing the export or import of a diverse array of molecules, and are involved in many plant responses to biotic and abiotic stresses. However, it is unclear whether PDRs are involved in Nicotiana attenuata resistance to the necrotic fungal pathogen Alternaria alternata. In this study, transcriptional levels of both NaPDR1 and NaPDR1-like were highly induced in N. attenuata leaves after A. alternata inoculation. Interestingly,silencing NaPDR1 or NaPDR1-like individually had little effect on N. attenuata resistance to A. alternata;however, when both genes were co-silenced plants became highly susceptible to the fungus, which was associated with elevated JA and ethylene responses. Neither NaPDR1 nor NaPDR1-like was significantly elicited by exogenous treatment with methyl jasmonate(MeJA), whereas both were highly induced by ethylene. The elicitation levels of both genes by A. alternata were significantly reduced in plants with impaired JA or ethylene signaling pathways. Thus, we conclude that both NaPDR1 and NaPDR1-like function redundantly to confer resistance against A. alternata in N. attenuata, and the elicitation of the transcripts of both genes by the fungus is partially dependent on ethylene and jasmonate signaling.

Identification of stably expressed QTL for resistance to black shank disease in tobacco(Nicotiana tabacum L.) line Beinhart 1000-1

Cigar line Beinhart 1000-1 has effective durable resistance to black shank(BS) and is considered one of the most resistant sources in tobacco(Nicotiana tabacum L.). To investigate the inheritance and identification of stable quantitative trait loci(QTL) for BS response, F2,BC1 F2 individuals and BC1 F2:3 lines were produced from a cross between Beinhart 1000-1 and Xiaohuangjin 1025. Two major quantitative trait loci(M-QTL) named qBS7 and qBS17 were repeatedly detected under different conditions. QTL qBS7 was mapped to the region between PT30174 and PT60621 and explained 17.40%–25.60% of the phenotypic variance under different conditions. The other QTL qBS17 in interval PT61564–PT61538 of linkage group 17 was detected in a BC1 F2 population in the field and in BC1 F2:3 in both the field and at the seedling stage, explaining 6.90% to 11.60% of the phenotypic variance. The results improve our understanding of the inheritance of resistance to BS and provide information that can be used in marker-assisted breeding.

Plant Resistance to Pest and Research Progress of Its Genetic Improvement

Pest damage is a significant factor that cuts agricultural production, and cultivation of pest-resistant varieties is the most economic and effective approach of controlling pest damage. Plant pest resistance includes antixenosis, antibiosis, and tolerance. Current popular methods for the genetic improvement of crop pest resistance are traditional breeding method, transgenic breeding, and molecular mark-assisted breeding. This paper introduced major mechanisms and genetic bases of plant pest resistance, ＂and reviewed research progress of domestic and international genetic improvement of plant pest resistance, analyzed the problems and its de- velopment prospects.

Genome-wide identification and expression analysis of GDSL esterase/lipase genes in tomato

The GDSL esterase/lipase family contains many functional genes that perform important biological functions in growth and development, morphogenesis, seed oil synthesis, and defense responses in plants. The expression of GDSL esterase/lipase genes can respond to biotic and abiotic stresses. Although GDSL esterase/lipase family genes have been identified and studied in other plants, they have not been identified and their functions remain unclear in tomato. This study is the first to identify 80 GDSL esterase/lipase family genes in tomato, which were named SlGELP1–80. These genes were mapped to their positions on the chromosomes and their physical and chemical properties, gene structure, phylogenetic relationships, collinear relationships, and cis-acting elements were analyzed. The spatiotemporal expression characteristics of the Sl GELP genes in tomato were diverse. In addition, RNA-seq analysis indicated that the expression patterns of the SlGELP genes in tomato differed before and after inoculation with Stemphylium lycopersici. qRT-PCR was used to analyze the expression of five Sl GELP genes after treatments with S. lycopersici, salicylic acid and jasmonic acid. Finally, this study was the first to identify and analyze GDSL esterase/lipase family genes in tomato via bioinformatics approaches, and these findings provide new insights for improving the study of plant disease resistance.

Evaluation of cotton germplasm for morphological and biochemical host plant UPdates resistance traits against sucking insect pests complex

Background:Sucking insect pests cause severe damage to cotton crop production.The development of insect resistant cotton cultivars is one of the most effective measures in curtailing the yield losses.Considering the role of morphological and biochemical host plant resista nee(HPR)traits in plant defense,12 cotton genotypes/varieties were evaluated for leaf area,leaf glanding,total soluble sugars,total soluble proteins,total phenolics,tannin and total flavonoids against fluctuating populations of whitefly,thrips and jassid under field conditions.Results:The population of these insects fluctuated during the growing seas on and remained above threshold level(whitefly>5,thrips>(8-10)f or jassid>1 per leaf)during late June and early July.Strong and negative association of whitefly(r=-0.825)and jassid(r=-0.929)with seed cotton yield was observed.Mean population of insects were the highest in Glandless-1 followed by NIA-82 and NIA-M30.NIAB-Kiran followed by NI AB-878 and Sadori were the most resistant,with the mean population of 1.41,1.60,1.66(whitefly);2.24,232,2.53(thrips)and 037,0.31,036(jassid),respectively.The resistant variety NIAB-Kiran showed less soluble sugars(8.54 mg.g^(-1)),soluble proteins(27.11 mg.g^(-1))and more phenolic(36.56 mg.g^(-1))and flavonoids(13.10mg.g^(-1))as compared with the susceptible check Glandless-1.Moreover,all insect populations were positively correlated with total soluble sugars and proteins.Whitefly populations exhibited negative response to leaf gossypol glands,total phenolics,tannins and flavonoids.The thrips and jassid populations had a significant and negative correlation with these four biochemical HPR traits.Conclusion:The ide ntified resistant resources and HPR traits can be deployed against sucking in sect pests'complex in future breeding programs of developing insect resistant cotton varieties.

Allelopathic Effect of Three Wild Plants (<i>Azadirachta indica</i>, <i>Tithonia diversifolia</i>and <i>Thevetia peruviana</i>) on Tomato (<i>Lycopersicum esculentum</i>Mill.) Growth and Stimulation of Metabolites Involved in Plant Resistance

The aim of this study was to determine the allelopathic effects of Azadirachta indica oil and aqueous extracts of Tithonia diversifolia and Thevetia peruviana on the growth and stimulation of metabolites involved in tomato plant resistance. Randomized in blocks within a shaded area, the different treatments prepared at 10% and 15% (v/v and w/v) in water were subsequently applied on tomatoes seeds to monitor the effect on germination, and on tomatoes leaves to monitor the effect on growth and resilience of the plants. The result showed that in stressful conditions all the treatments significantly inhibit (p < 0.05) the germination capacity of the seeds from 21.22% to 92.61%, the germination rate from 39.82% to 92.76% and the germination viability of the seedlings from 64.67% to 100%. However, the negative allelopathic effect of the treatment was significantly reduced (p < 0.05) when used for germination initiation by botanical priming. In addition, while T. diversifolia at 10% promotes a better aerial and root growth in tomato plants, T. peruviana at 15% induces the activation of resistance mechanisms in tomato plants by increasing protein levels to 104.5%, phenol levels to 183.33% and peroxidase enzyme activity to 586.15%. Therefore, allelopathic compound of wild plants would be a good alternative for growth promotion and resistance of tomato crops.

Evaluating Protective Terpenoid Aldehyde Compounds in Cotton (Gossypium hirsutum L.) Roots

Cotton (Gossypium hirsutum L.) has epidermal glands containing terpenoid aldehyde (TA) compounds that protect the plant from pests and diseases. One TA, gossypol, has two forms (+) and (-) that are present in varying amounts. This study evaluated the variation in roots for TA compounds and how environment affected the levels of these compounds. Similar to seed, gossypol was the predominant TA in roots. No heliocides were detected with only trace amounts of other TAs, such as hemigossypolone or hemigossypol, detected in a few lines. Among the glanded lines, there were significant differences in gossypol content. Percent plus gossypol was consistently 4% - 10% higher in roots than seed. One line, “Mac7”, had 12 - 14 ug/mg gossypol in roots and 18 ug/mg in seed as well as >90% (+) gossypol in both roots and seed. Unlike other tissues in glandless cotton, the roots of glandless lines consistently produced detectable amounts of gossypol with 77% to 82% in the (+) form. Multi-year field tests showed that although gossypol levels in the roots were more affected by insect pressure or other environmental conditions than seed, there was selectable variation in upland cotton for root gossypol content. Unlike other parts of a glandless plant, the roots retained a functioning biochemical pathway for gossypol production.

The Resistance of Crops in Plant Protection

World crop production requires highly-productive varieties of agricultural crops,which are resistant to pest organisms.Such varieties are also of great importance for the Uzbekistan.Their

Alectra vogelii: A Threat to Bambara Groundnut Production under Climate Change: A Review Paper

Bambara groundnut (BGN) is a protein-rich pulse with the ability to lead to more climate-resilient agriculture. The objective of this study was to review Alectra vogelii as a potential threat to BGN production as a result of climate change. However, the crop faces biotic and abiotic stresses. Alectra vogelii is a major biotic constraint to BGN production, especially in Africa’s non-fertile semi-arid regions. Alectra vogelii (L.) Benth is a parasitic weed in the Orobanchaceae family that causes major damage by forming haustoria attached to roots to enable absorption of nutrients from the BGN. Alectra vogelii produces a large number of minute seeds that can live in the soil for up to 20 years. Based on the reviewed literature, various control mechanisms for dealing with the harmful effects of Alectra vogelii have been proposed. The aim of this research was to reveal the effect of Alectra vogelii on BGN and possible control strategies. We discuss the different control methods such as cultural and mechanical management procedures, phosphorus fertilizers and resistant host crops, herbicide use, and integrated Alectra vogelii control methods. In adaptive methods, however, new techniques remain important. The life cycle of root parasitic weeds is inextricably linked to that of their host, making it an ideal target for such new control techniques, especially when aimed at the early stages of the host-parasite relationship. This review reveals additional information on the function of parasitic seed, strigolactones and how they can be used in breeding to management parasitic weeds.

Flavonoid-producing tomato plants have a direct negative effect on the zoophytophagous biological control agent Oriussauteri

Orius sauteri(Poppius)(Hemiptera:Anthocoridae)is often used for biological control of small arthropod pests in greenhouse vegetable production systems in Asia.In addition to feeding on arthropod prey,O.sauteri consumes small quantities of plant material.Previous studies demonstrated that tomato plant chemistry confers antixenosis resistance to phloem-feeding whiteflies,but the potential nontarget effects of phytochemicals on the beneficial predator O.sauteri are unknown.Comparison of O.sauteri confined to near-isogenic lines(NILs)of tomatoes producing high levels offlavonoids(NIL-purple hypocotyl;resistant to whiteflies)and low levels of flavonoids(NIL-green hypocotyl;susceptible to whiteflies)revealed that O.sauteri had reduced oviposition,nymphal survival,and development on resistant plants,even if they were also provided with prey that did not feed on the host plant.Moreover,O.sauteri showed a significant ovipositional preference in choice assays,laying significantly more eggs on susceptible than on resistant plants.Molecular gut content analysis using the specific chloroplast trnL gene from tomato confirmed that adult and immature O.sauteri feed on both resistant and susceptible genotypes,and feeding behavior assays revealed that resistance did not affect plant feeding or prey acceptance by O.sauteri adults.These results demonstrate a direct negative effect of phytochemicals on a nontarget beneficial species and indicate that resistance mediated by phytochemicals can affect organisms that do not solely feed on phloem sap.The results also indicate that the mode of action and the potential ecological effects of phytochemicalmediated resistance are broader than previously recognized.

Sugarcane Transcript Profiling Assessed by cDNA-AFLP Analysis during the Interaction with Sugarcane Mosaic Virus

Sugarcane mosaic caused by Sugarcane Mosaic Virus (SCMV) is one of the most important virus diseases of sugarcane. In the present study, changes in the transcription profile obtained by cDNA-AFLP analysis were investigated in two sugarcane varieties contrasting to SCMV resistance, when challenged with a severe virus strain. Healthy plants derived from meristem tip tissue culture were mechanically inoculated under greenhouse controlled conditions and sampled at 24, 48 and 72 hours after inoculation. A total of 392 transcript-derived fragments (TDFs) were verified in the resistant variety against 380 in the susceptible one. The two sugarcane genotypes showed differential behavior in the number of induced and repressed TDFs along the time-course samplings. Ten out of 23 sequenced TDFs (unique from the resistance variety), showed identity with known plant sequences, mostly related to plant defense mechanisms against pathogens. The cDNA-AFLP technique was effective in revealing changes in the transcription profile within and between contrasting varieties when challenged by SCMV.