Environmental Efficiency Analysis of China’s Vegetable Production

To analyze and estimate the environmental efficiency of China’s vegetable production. Methods The stochastic translog frontier model was used to estimate the technical efficiency of vegetable production. Based on the estimated frontier and technical inefficiency levels, we used the method developed by Reinhard, et al.[1] to estimate the environmental efficiency. Pesticide and chemical fertilizer inputs were treated as environmentally detrimental inputs. Results From estimated results, the mean environmental efficiency for pesticide input was 69.7%, indicating a great potential for reducing pesticide use in China’s vegetable production. In addition, substitution and output elasticities for vegetable farms were estimated to provide farmers with helpful information on how to reallocate input resources and improve efficiency. Conclusion There exists a great potential for reducing pesticide use in China’s vegetable production.

Sequence Analysis of mtDNA CO/Gene and Molecular Phylogeny of Different Geographical Populations of Bemisia tabaci (Gennadius)

Bemisia tabaci(Gennadius) is a serious pest in many cropping systems worldwide and occurs in different biotypes. ThemtDNA COI gene of the 12 Bemisia tabaci (Gennadius) populations from different regions and countries were analyzed.Based on mtDNA COI sequences, their biotypes were characterized and phylogenetic relationships among thesepopulations were established with the method of UPGMA. The results indicated the genetic similarity between thosepopulations from Beijing, Zhengzhou, Zaozhuang, Nanjing, Shanghai, Haikou, and the B-biotype populations fromCalifornia, Texas, Arizona reached 99.8-100%, which meant the nation-wide infested populations of B.tabaci in China inrecent years were B-biotypes. Another population collected from Kunming of Yunnan Province showed very high similaritywith Q-biotype B.tabaci from Spain and Morocco, which meant the Kunming population was Q-biotype. This is the firstreport on the invasion of Q-biotype into China.

Diversity of Trichoderma in greenhouse soil

The protected agricultural production has become one of the fast growing and wid espread cultivation technology in the north parts of China. Continuous cultivati on of single crop or less rotation of crops usually resulted in the large amount of accumulation of soilborne pathogens and serious crop diseases in the greenho use. After a few years of investigation of soilborne fungi in the north parts of China, nearly one hundred species of mictosporic fungi have been identified by the authors. Among these fungi 11 species of Trichoderma have been morphol ogically identified, namely T. atroviride, T. aureoviride, T. citrinoviride, T. fertile, T. harzianum, T. inhamatum,T. longibrachiatum, T. parceramosum, T. r eeseii, T. virens and T. viride. Trichoderm is found to be a frequently occurring genus of fungi in greenhouse soil. As an important component of effec tive beneficial antibiotic mycoparasites in soil Trichoderma plays an impo rtant part to regulate the balance of beneficial and harmful soilborne microorga nisms.

Effect of microelement and chemical fungicides on biocontrol effect of Trichoderma T23

Recently there have been many reports about soil diseases controlled by Trichoderma, but few could be applied on agriculture production in large areas. T23 isolated from soil around plant roots in the field by Biopesticide Engineering Center of Shenyang Agricultural University could control effectively Cucurbits Fusarium Wilt. The effects of 9 microelements which include copper, zinc, iron, boron, molybdenum, calcium, manganese, magnesium, potassium and frequently-used chemical fungicides, such as-carbendazim, thiram, thiophanate-methyl, chlorothalonil and hymexazol on the growth and the amounts of spores of Fusarium oxysporum FJ and Trichoderma T23 were studied. The effects of those factors on control effect of T23 to melon diseases were discussed and gave basis for the screening of synergistic agents and fungicides in controlling synergistically the pathogen. The results showed that copper sulfate, zinc sulfate, ferric sulfate and boric acid at concentration of 10-1000 μg/mL had the stronger inhibition to F. oxysporum, while weaker inhibition to Trichoderma. Ammonium molybdate, ferrous sulfate, calcium sulfate and potassium dihydrogen phosphate were the ideal the synergistic agent for accelerating the growth and sporulation of Trichoderma, and germination of melon seeds and growth of melon radicle. Melon Fusarium wilt was controlled by Trichoderma combined with ammonium molybdate and calcium sulfate. The relative control effect reached to 73.95%-71.36%. Several fungicides used generally in soil had a different effect on the growth of F. oxysporum and Trichoderma. Carbendazim appeared a strong inhibition to the growth of two strains, with EC50 of 3.01 mg/L and 0.75. mg/L, respectively. Trichoderma had the strong resistance to thiram which control to Fusarium oxysporum was not ideal in field. Hymexazol which EC50 was 261 mg/L and Trichoderma had the synergistical effect on controlling to F. oxysporum. Trichoderma could reproduce in soil treated with hymexazol at ratio of 2000-4000. Relative control effect of hymexazol combined with Trichoderma to oxysporum reached to 79.26%,. which was higher by 15.19% and 38.75% than the solo controlling effect respectively.

Construction of engineering Trichoderma strains and their characteristics against tomato gray mold

The transformed Trichoderma strains Ttrm31, Ttrm34 and Ttrm55 were obtained from Trichoderma wild strain T21 mutated by REMI technique for more effective biocontrol of tomato gray mold (Botrytis cinerea) with Trichoderma agent. Those transformants appeared much better in biocontrol activity in vitro or in vivo against tomato gray mold were better than that of wild strain T21. The main results were as follow: The transformed Trichoderma strains were detected in their genetic stability by consecutive culture for several generations, growing them on hygromycin-contained medium, and then further detection by PCR. The results showed that the REMI was very useful to construct the transformed Trichoderma strains even though some non-transformants concurrently appeared with positive reaction, but which could be distinguished and avoided by southern blotting. The biological characteristics of transformed Trichoderma strains varied among themselves or differed in parts as compared with wild one. Much changes were detected in the conidia germination, sporulation, tolerance to high-temperature, growth at a certain range of temperature, cultural characteristics under different pH condition as well as utilization of carbon and nitrogen nutrition. Some transformants performed better in the most of mentioned characteristics compared with wild one, others not. For example, conidia germination of strain Ttrm31 was higher than that of wild strain T21. Conidia productivity of Ttrm34 was higher than that of wild strain T21. As the tolerance to high-temperature, Ttrm31 and Ttrm34 were enhanced remarkably relative to wild strain. Meanwhile, it was interested that the growth of transformed Trichoderma strains improved much once treated under high-temperature (50℃) for 1 h. Differently, Ttrm55 grew faster at low-temperature (15℃) ,Ttrm31,Ttrm34 and Ttrm55 grew fast as the wild one at 20-30℃. The transformed Trichoderma strains differed in cultural morphology including color and sporulation at different pH, and even on PDA. Protein and asparagines were screened as better nitrogen, and glucose and maltose as better carbon source. There were several mechanisms expected among transformed Trichoderma strains against Botrytis cinerea. Ttrm31, Ttrm55 and Ttrm111,for instance, had more ability for the nutrition and space competition over pathogen, while Ttrm34 and Ttrm76 inhibited pathogen in the way of mycoparasitism which subsequently confirmed by the higher activities of chitinase and β-glucanase needed for parasitizing pathogen. Similarly Ttrm34 and Ttrm55 were higher in both enzyme activities than those of T21. Additionally a putative role of induced resistance might be involved in the biocontrol mechanism because a series of defensive enzyme in tomato were increased in activities such as PAL, POD, CAT, PPO, SOD, chitinase and β-glucanase once tomato plants treated with transformants, but the level of the induction depended on the transformed Trichoderma strains used. Comparatively, PAL, POD, CAT, PPO and chitinase activities in tomato induced by Ttrm55 were great different from other transformants except SOD and β-glucanase. SOD activity in tomato stimulated by strain Ttrm55 was higher than that induced by others, while β-glucanase activity was lower. The CAT, PAL, PPO activities induced by Ttrm31 were higher than those by other transformants, but lower in SOD, POD and chitinase than those by others. In general POD, PPO, PAL and chitinase activities were higher in tomato induced by Ttrm34 than other enzymes. β-glucanase activities induced by T21 were higher than those of others, but contrary in other enzymes. Transformed Trichoderma strains had the same ability in the colonization on the tomato leaf surface as the wild strain T21, however no much differences were seen between transformants and wild one in the trait. More importantly 3 transformed Trichoderma strains were proved to be very effective in the control of gray mold in flowers and leaves and 14%-18.5% and 7%-9% were increased over wild strain

The Relationship Between Resistance to Controlled Atmosphere and Insecticides of Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae)

The cross resistance of four resistant strains of Liposcelis bostrychophila Badonnel, an important stored-product insect pest, was investigated. These four strains included the HCO2-R (hypercarbia-resistant strain), HCLO-R (hypoxia and hypercarbia resistant strain), DDVP-R (DDVP-resistant strain) and PH3-R (PH3-resistant strain). The results indicated that there were cross-resistances between CA and insecticides, and the quantities of the cross-resistance were different. The cross-resistance factor (RF) of HCO2-R to hypoxia and hypercarbia was 3.2458, whilst, that of HCLO-R to hypercarbia was 1.8280. The RF of DDVP-R to PH3 was 3.9614, whilst, that of PH3-R to DDVP was 2.7852. The RF values of DDVP- R and PH3-R to hypercarbia were 1.3550 and 1.1816, respectively. However, the RF of HCO2- R to DDVP was 2.1372. There also was a low cross-resistance between DDVP-R and HCO2-R. The RF of HCO2-R to PH3 was 3.3698. This suggested that the insects resistant to high CO2 concentration atmosphere would develop significant resistance to PH3. However, the insects resistant to PH3 remain sensitive to hypercarbia atmosphere. Both DDVP-R and PH3- R developed resistance to high CO2 treatment. There was a low cross-resistance between DDVP-R and HCLO-R. The insects resistant to hypoxia and hypercarbia were very sensitive to DDVP. There also was cross-resistance between HCLO-R and PH3-R, but the resistance of PH3-R to hypoxia and hypercarbia was lower than that of HCLO-R to PH3. The difference of the overlapping and separate values indicated that there were differences in the intercross-resistance of four resistant strains.

Changes in Cell Ultrastructure in Maize Leaves Infected by Maize Dwarf Mosaic Virus

Ultrastructural alterations in foliar cells were studied in leaves of resistant maize variety Luyu16 and susceptible maize inbred line Luyuan92 infected by maize dwarf mosaic virus Shandong isolate (MDMV-SD), respectively. The results showed that marked cytopathological alterations were observed both in resistant plants and in susceptible plants, compared with that in healthy plants. However, some ultrastructural alterations, which observed in resistant plants, were different from those in susceptible plants. In resistant plants, which infected with the virus, the main organelles, including chloroplasts and mitochondria, were slightly destroyed, the amount of mitochondria and peroxisome were increased. A few or no plasmodesmata were observed. There were three kinds of inclusions including pinwheel, bundle and laminated aggregate, and the virus particles in the cytoplasm. In susceptible plants, which infected with the virus, the chloroplasts were heavily disrupted, including thylakoid swelling and envelope broking. The virus particles were more than those in the resistant variety. Four kinds of inclusions including pinwheel, bundle, laminated aggregate and high electon-dense body appeared in cytoplasm. Plasmodesmata and plasma membrane were abundant, and there were frequent invaginations of the plasma membrane that led to the formation of vesicles and myelin-like structures.

Comparison of PCR, DIA and Pathogenicity Assay for Detection of Xanthomonas axonopodis pv.citri,the Causal Agent of Citrus Bacterial Canker Disease

Polymerase chain reaction (PCR) approach based on newly designed primers, JYF5/JYR5, wasapplied for specific detection of Xanthomonas axonopodis pv.citri(Xac). The efficiencyand reliability of PCR method were compared with dot immunobinding assay (DIA) andclassical pathogenicity test techniques for detecting suspensions of pure cells of Xacand soaking sap of citrus tissues. Detection sensitivity of PCR was about 4.5 cells or1.56 pg target DNA per reaction which was higher than that of DIA (ca. 450 cells per dot).These three techniques (PCR assay, DIA and Pathogenecity test) could always detect Xacfrom symptomatic citrus samples. Different performances were obtained from citrusmaterials without symptoms, and the positive detection frequency was PCR, DIA andpathogenicity test.

Screening of Trichoderma strains tolerant to benzimidazole

The screening of isolates and the assay of biocontrol mechanisms of Trichoderma were studied systematically in laboratory and greenhouse in vivo. The proteins tolerant to benzimidazole in Trichoderma strains were purified, and their physical and chemical properties were detected. Compared their biological activities in vitro and vivo in greenhouse, nine biocontrol strains (including Ty-10-2,LTR-2,Tj-5-1,Tj-5-4,Ty-11-1,Tj-11-3,Ty-11-3,Tj-3-3-2,Tj-3-3-4) were screened. These biocontrol strains had faster rates of growth and higher inhibition to gray mould (Bortrytis cinerea), and the inhibition was stable. The effects of controlling gray mould in greenhouse with the screened Trichoderma strains were 70% and 50% in vivo. Induced by the substrates including benzimidazole, UV rays and nitrosoguanidine, four strains were screened. They were Ty-10-2,LTR-2,Tj-5-4,Ty-11-3. After being cultured for 24 h, conidiospores of tolerant strains germinated but the sensitive ones didn’t. Compared with the hyphae of the tolerant strains, the sensitive hyphae, front became thinner and shorter. Experiments of biocontrol mechanisms showed as followed: some genes had mutated, transcripted at different levels and translated into some tolerant proteins, while some genes had opposite changes. In the whole, the soluble proteins in cells had increased in quantity. The esterase isoenzymes in the tolerant strains decreased at different levels. After being induced, some genes mutated and some genes, transcription decreased and even diminished. None were screened from UV rays and nitrosoguanidine.

Effect of Trichoderma viride on activities of polygalacturonase of Rhizoctonia

The pectin is a backbone of the plant cell wall, its network structure will systemicly resolve when the plant cell splits up and forms. The pectinase produced by Rhizoctonia mainly acts on the pectin of cell wall, and causes the maceration of tissue and the death of protoplast. Polygalacturonase (PG) can decompose the galacturonic acid of disease tissue. The research defined the PG activities of extracellular metabolite of the different virulence Rhizoctonia isolates, and testifid the effect of Trichoderma viride to PG activities, and clarified the mechanisms of biocontrol by Trichoderma. The test methods as following: Firstly, to select the isolates of different virulence: WK-47, WK-141 and WK-160 strain of Rhizoctonia AG-D and YW-2 strain of Rhizoctonia AG1-IA and TCS-1 strain of Trichoderma viride. Secondly, to culture TCS-1 on PD, and draw a group of fermented liquid in every 24 hours, and draw 7 times. Thirdly, to culture quietly Rhizoctonia isolates with Czapek-Dox at 25℃ for 15 days, filter and centrifuge (2350 g×30 min), fetch the clear liquid, put it into the ammonium sulfate according to 60% saturation degree, put it quietly for 30 min at 4℃, centrifuge (21000 g×30 min) at 4℃, remove the clear liquid, dissolve the deposit with sodium acetate buffer (25 mmol/L, pH5.5), dialysis for 48 h in the same buffer,and change the buffer every 12 h, Fourthly, to put TCS-1 fermented broth of different times in the tubes, one mL per a tube, add 0.5 mL PG to every tube, react for 4 h in 30 ℃ water, the same time fetch the test tube filled with the same treated liquid that was not dealed in 30℃ water.Finally,to testify PG activities with DNS’s test. In all, PG of Rhizoctonia had high activities and virulence. The conrtrol efficacy of T.viride to PG activities of WK-47, WK-141, WK-160 and YW-2 were 95%,94%,95%,92% separately, fermented time had a great influence to control efficacy, the third fermented broth did the best. Through effect to PG activities T. viride can reduce the virulence of Rhizoctonia, and protect the hosts. The specific mechanism, qualitative and quantitative research of antagonistic substance in the fermented broth will be further carried out.

Gliocladium and Trichoderma in agricultural soil

Gliocladium and Trichoderma are common fungi in agricultural soil. Several species of them were isolated and identified, great diversity was displayed in different agricultural soils of different crops, agricultural climate zones, different seasons, depths, different treated soybean cyst nematode soil, healthy and diseased crop soil. Among five crops soil samples, wheat and corn soil were found to possess the largest number of Gliocladium and Trichoderma separately. Gliocladium and Trichoderma of three major crops showed consistent changing patterns with seasonal variation. Corn soil displayed distinct vertical distribution of Trichoderma. There is a different distribution of the two fungi in diseased and healthy plant soil. Among the various isolated methods, diluted plate method is the best for isolating Gliocladium, and Trichoderma could be found in plant residue method and be tolerant to steam for two minutes. In the soybean cyst nematode soil mycobiota, the frequency of Gliocladium is higher than that of the others fungi, and Trichoderma may have the role of bioremediation in herbicide treated soil. Similarly, Gliocladium occurred frequently in different climate zones.

Studies on the control of Fusarium oxysporum f.sp. cubense with Trichoderma

One hundred and fifty one isolates of Trichoderma were collected mainly from more than 40 soil samples and other materials in Guangdong Province (including Chigang, Zhanjiang, Wuchuan, Panyu, Zhaoqing, Dongguan, Humen, Qingyuan, Guanzhou) and the soil samples were also from different plant rhizosphere (including rice, different fruits and different vegetables). It was shown that 39 isolates of Trichoderma grew faster than other isolates using growth velocity experiments. The 39 isolates could effectively inhibit Fusarium oxysporum f.sp. cubense (E.F.Sm) Sny.&Hans. by dual cultural experiments. The inhibited activity included the antifungal activities of its metabolite, mycoparasitic activities and the lytic enzymes by dual culture, electronic microcopy and enzyme assay. At present, studies on the taxonomy of the 151 isolates of Trichoderma are carried out in our experiments, some Trichoderma species aggregates will be identified according to the taxonomy system revised by Rifai and Bissett.

Study on the character of chitinase produced by Trichoderma spp. with measuring reducing sugar

A trusty and intuitionistic method for screening chitinase produced by Trichoderma spp. was developed. 38 isolates of Trichoderma spp. were cultured in liquid medium with chitin or colloidal chitin as the sole carbon source for 4 days. The supernatant of the fermented broth was mixed with colloidal chitin and heated in water-bath at 37℃ for 30 min, then 3,5-dinitrosalicylic acid reagent (DNS) was added to the mixture, and let them react for 10 min in water-bath. According to the different colour of the mixture, the isolates of Trichoderma spp. which can produce chitinase could be screened.

Ultrastructure of Slow-Rusting Expression of Wheat to Stripe Rust

The ultrastructure of wheat cultivars with slow-rusting resistance expression to the stripe rust, Puccinia striiformis, wasstudied through TEM. The results show that slow-rusting has the same hypersensitive response characters with the lowinfection type resistance, but the mesophyll cell necrotized less in number, thereby only partially inhibiting the extensionof rust fungus, and the fungus being inhibited and necrosed slighter in degree. Apart from the occurrence ofhypersensitiveness, the response of the host cells in slow-rusting wheat cultivars to the infection of fungus also producesstructural materials associated with defense reaction, but distinctly less than that in resistant cultivar. Thus, it is suggestedthat the slow-rusting resistance might have a similar mechanism with the low infection type resistance of race specificity,but with lower intensity.

Resistance to Bacterial Leaf Blight in a Somaclonal Rice Mutant HX-3 at Cellular Level

The interaction between rice host and its pathogen Xanthomonas oryzae pv. oryzae (Xoo) at cellular level was studied by using a resistant somaclonal mutant HX-3 and its susceptable donor Minghui 63. After inoculation with Xoo strain Zhe 173 (Chinese pathotype Ⅳ), the activity of superoxide dismutase (SOD) and peroxidase (POD) in the callus of Minghui 63 was increased dramatically, and the active oxygen(O2 ) was produced at a higher rate; Meanwhile, the callus grew slowly with the reduction of protein content Compared to the activity of SOD and POD, the production rate of Oa and the fresh weight in HX-3 callus varied little after the inoculation It could be proposed that there were great differences between the resistance of HX-3 and Mighui 63 at cellular level. There was no difference detected concerning resistance to bacterial leaf blight in HX-3 between the plant and the callus.

Advances in Localization and Molecular Markers of Wheat Leaf Rust Resistance Genes

Genetic resistance is the most economical method of reducing yield losses caused by wheat leaf rust. To identify the leaf rust resistance genes in commonly used parental germplasm and released cultivars become very important for utilizing the genetic resistance to wheat leaf rust fully. Up to date, about 90 leaf rust resistance genes have been found, of which 51 genes have been located and mapped to special chromosomes, and 56 genes have been designated officially according to the standards set forth in the Catalogue of Gene Symbols for wheat. Twenty-four wheat leaf rust resistance genes have been developed for their molecular markers. It is very important to isolate, characterize, and map leaf rust resistance genes due to the resistance losses of the genes caused by the pathogen continuously.

CHANGES OF GLYCEROL CONTENT IN DIAPAUSE LARVAEOF THE ORANGE WHEAT BLOSSOM MIDGE, SITODIPLOSIS MOSELLANA （GEHIN） IN VARIOUS SEASONS

The glycerol contents in diapause larvae of the orange wheat blossom midge, Sitodiplosis mosellana (Gehin), collected from various seasons, were measured. The results showed that there was less glycerol content in larvae during living on the wheat head. Content of glycerol began to increase significantly when the larvae left the wheat head and entered the soil. A change trend of upper- lower- upper- lower in larvae glycerol contents during diapause in soil was observed from June to April of next year. More glycerol could be examined in larvae collected in summer and winter than in spring and autumn. There was not more glycerol in cocooned larvae than that in non-cocooned larvae during various seasons from the point of statistics. Comparing the glycerol content of larvae being diapause in the first year with that of larvae in the second year, there was yet no obvious difference when larvae were collected in the same season belonged to different years. Therefore, it is shown that the content of glycerol in larvae of the wheat midge in diapause is affected mainly by the seasons or diapause intensity.