Inhibitory effects on microbial growth of Botrytis cinerea and Erwinia carotovora on potato using of a biopolymer chitosan at different molecular weights

The antimicrobial efficiency of chitosan at different molecular weights (5, 37, 57 and 290 kDa) against Botrytis cinerea and Erwinia carotovora on potato (Solanum tuberosum L.) was investigated. In vitro study showed that chitosan of 37 kDa was the most active against E. carotovora (minimum inhibitory concentration (MIC) = 950 mg/L), whereas 5 kDa chitosan was the most active against B.cinerea. Coating of potato tubers with 100, 250 and 500 mg/L significantly decreased the rate of weight loss and chitosan of 37 kDa showed the best effect. The in vivo antibacterial effect indicated that all treatments (500, 1000 and 2000 mg/L) significantly inhibited the growth of E. carotovora compared with the control. The lowest decay incidence was observed with 37 kDa chitosan. However, the antifungal activity against B. cinerea inoculated of leaves showed no decay incidence at 500 and 1000 mg/L with 57 kDa chitosan after 48 h.     

Organic hydroponics induces systemic resistance against the air-borne pathogen,Botrytis cinerea (gray mould)

Here, we propose that organic hydroponics trigger induced systemic resistance (ISR) in lettuce against air-borne Botrytis cinerea, which causes gray mold. We compared effects of organic and chemical hydroponics, assessed presence of ISR elicitors in the hydroponic nutrient solution, and investigated molecular mechanism of ISR. Organic hydroponics significantly reduced gray mold lesions in lettuce (cultivated hydroponically) and cucumber (cultivated in soil and foliar sprayed with nutrient solution). The 1-aminocyclopropane-1-carboxylic acid synthase gene in lettuce and lipoxygenase and ethylene receptor-related gene in cucumber showed heightened expression, suggesting that the jasmonic acid/ethylene (JA/ET)-signaling pathway was involved in ISR for both crops. Low salicylic acid β-glucoside levels confirmed role of the ISR signaling pathway. ISR in both lettuce and cucumbers indicated that elicitors in organic hydroponics were nonhost-specific and that the JA/ET pathway was activated without microbe–root interaction. Thus, organic hydroponics can be an effective method for both soil-borne and air-borne disease control.     

Extracellular Carbohydrate Esterase from the Basidiomycete Coprinopsis cinerea Released Ferulic and Acetic Acids from Xylan

cDNA encoding an extracellular carbohydrate esterase (CcEst1) was cloned from the basidiomycete Coprinopsis cinerea. The recombinant CcEst1 expressed in Pichia pastoris acted on p-nitrophenyl acetate, α-naphthyl acetate, and methyl hydroxycinnamic acids, except for methyl sinapic acid. The enzyme released ferulic and acetic acids from wheat arabinoxylan and acetylated xylan respectively. Activity increased on the addition of endo-β-1,4-xylanase.     

Gibberellin A36, Isolation from Gibberella fujikuroi,Structure and Conversion to Gibberellin A37

A cDNA encoding a putative extracellular α-L-arabinofuranosidase was cloned from the basidiomycete Coprinopsis cinerea (CcAbf62A). CcAbf62A belongs to glycoside hydrolase family 62 (GH62), but is phylogenetically distinct from previously characterized GH62 enzymes. The recombinant CcAbf62A, expressed in Pichia pastoris, released L-arabinose from both wheat arabinoxylan and oat-spelt xylan. The enzyme activity for wheat arabinoxylan was increased by the addition of CcEst1, a carbohydrate esterase from C. cinerea.     

Jaburetox,a urease-derived peptide: Effects on enzymatic pathways of the cockroach Nauphoeta cinerea

Jaburetox is a recombinant peptide derived from one of the Canavalia ensiformis urease isoforms. This peptide induces several toxic effects on insects of different orders, including interference on muscle contractility in cockroaches, modulation of UDP-N-acetylglucosamine pyrophosphorylase (UAP) and nitric oxide synthase (NOS) activities in the central nervous system of triatomines, as well as activation of the immune system in Rhodnius prolixus. When injected, the peptide is lethal for R. prolixus and Triatoma infestans. Here, we evaluated Jaburetox toxicity to Nauphoeta cinerea cockroaches, exploring the effects on the central nervous system through the activities of UAP, NOS, acid phosphatases (ACP), and acetylcholinesterase (AChE). The results indicated that N. cinerea is not susceptible to the lethal effect of the peptide. Moreover, both in vivo and in vitro treatments with Jaburetox inhibited NOS activity, without modifying the protein levels. No alterations on ACP activity were observed. In addition, the enzyme activity of UAP only had its activity affected at 18 hr after injection. The peptide increased the AChE activity, suggesting a mechanism involved in overcoming the toxic effects. In conclusion, our findings indicate that Jaburetox affects the nitrinergic signaling as well as the AChE and UAP activities and establishes N. cinerea as a Jaburetox-resistant model for future comparative studies.     

Protease inhibitors clitocypin and macrocypin are differentially expressed within basidiomycete fruiting bodies

Clitocypin and macrocypin are cysteine protease inhibitors of the mycocypin family which is unique to basidiomycetes. We have established that Clitocybe nebularis and Macrolepiota procera each contain genes for both macrocypin and clitocypin. Both are expressed in M. procera but only clitocypin in C. nebularis. Further analysis of mycocypin expression at the mRNA and protein levels in mature fruiting bodies of M. procera revealed that clitocypin is expressed evenly throughout the fruiting body, while the level of expression of macrocypins varies, and, at the protein level, is much higher in the veil fragments and the ring. The expression patterns of various mycocypins were determined in Coprinopsis cinerea, using promoters linked to a reporter gene. The expression profile of the clitocypin promoter was similar to that of the constitutive promoter gpdII from Agaricus bisporus, while that of the macrocypin 4 promoter was limited to the outer edges of the fruiting body throughout development. In addition, the activity of the macrocypin 3 promoter was different, indicating different regulation of expression for different macrocypin genes. The complex, tissue specific expression patterns for mycocypin genes suggest different biological roles for the products, either in regulation of endogenous proteases or in defense against pathogens or predators.     

Lower Temperatures More Effective than Atmosphere Modification in Controlling Botrytis and Nectria Rots in Stored Apples

A series of small‐scale controlled inoculation experiments has been conducted during 2005–2009 to determine whether temperature and controlled atmosphere (CA) storage conditions affect significantly the incidence of Botrytis cinerea and Neonectria galligena rots of apples and to assess whether CA regimes can be ‘fine‐tuned’ to suppress fungal rotting. The incidence of B. cinerea and N. galligena rots on apple was reduced consistently by storage in lower temperatures (1.5–2°C). In no case was the disease incidence significantly higher than that under air storage conditions. However, the effect of CA conditions on rot development varied greatly from year to year so that overall there were no significant effects of CA conditions on the incidence of rot during storage till the following April. Thus, we can neither fine‐tune CA conditions to reduce rot development nor exploit the advantages of lower storage temperatures for Cox and Bramley for this purpose due to inevitable development of low temperature breakdown. Further research is needed to study the effects of ethylene control technologies and modulated storage temperatures on rot development.