Manipulation of host S-nitrosylation by Pseudomonas syringae

Nitric oxide (NO) and S-nitrosothiols (SNOs) are widespread signalling molecules that regulate immunity in animals and plants (Wendehenne et al., 2001). Previously, we have reported that Arabidopsis thaliana S-nitrosoglutathione reductase, (AtGSNOR1) modulates the extent of total cellular SNO formation, which subsequently regulates multiple modes of plant disease resistance (Feechan et al., 2005). Loss-of-function mutations in AtGSNOR1, leading to increased SNO levels, have recently been shown to result in S-nitrosylation of the key defence regulators NPR1 and AtSABP3, blunting their activity and subsequently leading to increased pathogen susceptibility (Tada et al., 2008; Wang et al., 2009). Thus, inhibiting AtGSNOR1 function leading to increased SNOs, would potentially provide a good strategy for bacterial effector proteins, delivered by the type III secretion system (TTSS), to promote infection. AtGSNOR1 is constitutively expressed in all organs in Arabidopsis and its expression is induced by wounding stress avirulent and non-host pathogen. Using gas phase chemiluminescence, we show that infection with Pseudomonas syringae pv. tomato strain DC3000 (PstDC3000) resulted in increase SNO levels which is TTSS. At the same time, RT-PCR and GUS analysis indicated that AtGSNOR1 expression was transiently suppressed by PstDC3000 which is also TTSS-dependent. Therefore, PstDC3000 infection suppresses denitrosylase function of AtGSNOR1 to increase SNO levels and this virulence effect is delivered by at least one of the effector protein secreted through TTSS. Several putative cis-acting elements were identified in AtGSNOR1 promoter through deletion analysis including GT-box, W-box and MYB/MYC binding motif. These elements comprise of positive and negative regulators which are critical for the induction and suppression of AtGSNOR1 in response to pathogen infection. A few transgenic plants expressing effector proteins were selected and tested for their suppressive effect on AtGSNOR1 expression during PstDC3000 infection. HopAM1 effector proteins showed the ability to suppress AtGSNOR1 when expressed in planta

Nitric oxide and its important role in plant defence

Nitric oxide (NO) is a signaling molecule involved in numerous physiological processes in both animals and plants. The bioactivity of NO is mainly transduced via post-translational modification of cysteine residues of proteins termed S-nitrosylation. Interestingly, a number of key regulatory components in plant defense responses have been found to be regulated by S-nitrosylation making this type of protein modification an important modulator of plant immunity. As a signaling molecule, NO intimately interact with other important molecules such as reactive oxygen species. Since the identification of NO in plants, increasing number of papers is being published in the area of NO biology each year. Here, a collection of papers describing the role of NO in plant immunity has been brought together to provide a bird's-eye view on the focus area

Nitric oxide and Its Important Role in Plant Defence

Nitric oxide (NO) is a signaling molecule involved in numerous physiological processes in both animals and plants. The bioactivity of NO is mainly transduced via post-translational modification of cysteine residues of proteins termed S-nitrosylation. Interestingly, a number of key regulatory components in plant defense responses have been found to be regulated by S-nitrosylation making this type of protein modification an important modulator of plant immunity. As a signaling molecule, NO intimately interact with other important molecules such as reactive oxygen species. Since the identification of NO in plants, increasing number of papers isbeing published in the area of NO biology each year. Here, a collection of papers describing the role of NO in plant immunity has been brought together to provide a bird's-eye view on the focus area

Effects of herbicides on fungal phytopathogens

Herbicides are inevitable inputs to control excessive weed in crop land, particularly where modern agricultural practices such as conservation tillage, are opted. Intensive farming has increased the market value of herbicides among the other pesticides. Although herbicides are effective in controlling weed population, administration of this synthetic chemicals may alter the soil microbial community causing potential increase of plant pathogens. Moreover, herbicides may also have nontarget effects on the cultivated crops making them more susceptible to diseases. Actions of herbicides in soil that either stimulate microbial growth or wipe out some microbial population may create space for the thrivial of opportunistic fungi. Previous studies showed that white rot fungi are more tolerant to herbicides as they produce lignin degrading enzymes that are highly oxidative, non-specific and are able to transform a wide range of herbicides. Besides that, this group of fungi can grow on agricultural waste substrates. Influence of these herbicides on soil microbial ecosystem and interactions of plants and pathogenic white rot fungi modulate disease development in plant hosts

Deletion studies for elucidating the role of Streptomyces griseus ChiC non-catalytic residues

The soil bacterium, Streptomyces griseus, produces an antifungal chitinase (SgChiC) which has a smaller catalytic domain (in addition to a chitin binding domain) when compared with its counterparts from plants. Here, we carried out rational deletion of residues distant from the active site residues in the catalytic domain from 205 to 49 amino acid residues. The truncated residues were reconstructed and its 3-dimendional model predicted by homology modeling. In an insilico binding study, tri-N-acetyl glucosamine ((GlCNAc)3) was observed to bind to the active site of the truncated model similarly as in the wild type catalytic domain. This suggests that the variant model of SgChiC with a truncated catalytic domain possibly retains its chitinolytic properties. Further analysis of the simulation results revealed an increase in conformational space and flexibility of the reconstructed model over the less dynamic structure of the wild-type model. This suggests that the deleted residues played a role in the compactness and rigidity of the domain. Experimental assays to investigate the hydrolytic and kinetic properties of this truncated variant are currently been carried out. Outcomes of this study will reveal the relationship between the architecture of the ChiC domain and its function. This will guide future design studies for the enhancement of its functional properties and consequently its efficiency as a biocontrol agent.

Kids array

Children have limitless imagination, and drawing can be one the ways in which they can be creative. In order to compare the effect of psychology and environment, between urban and rural children, forty 10-year-old schoolchildren were assigned to draw their interpretation of “bird” on a long paper scroll. A drawing could reveal how children feel about their environment. Interestingly, the patterns of drawing of each group were relatively consistent. A majority of female schoolchildren from urban school drew imaginative forms of bird, flying freely

Deep learning sensor fusion in plant water stress assessment: A comprehensive review

Water stress is one of the major challenges to food security, causing a significant economic loss for the nation as well for growers. Accurate assessment of water stress will enhance agricultural productivity through optimization of plant water usage, maximizing plant breeding strategies, and preventing forest wildfire for better ecosystem management. Recent advancements in sensor technologies have enabled high-throughput, non-contact, and cost-efficient plant water stress assessment through intelligence system modeling. The advanced deep learning sensor fusion technique has been reported to improve the performance of the machine learning application for processing the collected sensory data. This paper extensively reviews the state-of-the-art methods for plant water stress assessment that utilized the deep learning sensor fusion approach in their application, together with future prospects and challenges of the application domain. Notably, 37 deep learning solutions fell under six main areas, namely soil moisture estimation, soil water modelling, evapotranspiration estimation, evapotranspiration forecasting, plant water status estimation and plant water stress identification. Basically, there are eight deep learning solutions compiled for the 3D-dimensional data and plant varieties challenge, including unbalanced data that occurred due to isohydric plants, and the effect of variations that occur within the same species but cultivated from different locations

Protein extraction protocol from Musa sp. shoots and roots tissue for non-reducing one dimensional SDS-PAGE analysis

Background: Protein extraction from plant tissues is a great challenge since they contain low amount of proteins and rich in proteases, secondary metabolites and oxidative enzymes. Besides, dealing with limited amount of starting material would pose another challenge in getting high protein yield. The aim of this study is to determine the best protein extraction protocol for recalcitrant tissues of banana (Musa sp.) specific for non-reducing one dimensional SDS-PAGE analysis. Methods: Three protein extraction protocols were compared which include TCA-acetone, phenol and phosphate buffer saline (PBS) using small amount of starting material. Modifications were done to each protocol to suit non-reducing SDS-PAGE analysis and subsequent downstream processes. Results: Of the three protocols compared, TCA-acetone protocol gave the highest yield and quality of protein extract from only a small amount of starting material based on protein quantification and non-reducing one dimensional SDS-PAGE analysis compared to phenol and phosphate buffer saline (PBS) protocol. Conclusion: Even though various protein extraction protocols have been developed to date, there is no one-size-fits-all when it comes to different types of plant tissues from varieties of plant species. TCA-acetone protocol was found to be most effective in extracting protein from banana shoot and root tissues even for small amount of starting material in absence of reducing agent

Potential of plant's Bowman-Birk protease inhibitor in combating abiotic stresses: a mini review

Bowman-Birk Inhibitor (BBI) is one of the subfamilies of serine protease inhibitors. Numerous studies have shown that in plants, BBI functions as part of their defense mechanism against pathogens and microorganisms. The BBI is also known to have anti-carcinogenic properties. Furthermore, the BBI has been reported to function in controlling abiotic stresses such as salinity and drought stresses. Abiotic stresses are the major problems in agricultural industry. Therefore, numerous researches have been carried out to characterize the BBI and to determine its roles during biotic and abiotic stresses. This paper presents a review regarding the relationship between Bowman-Birk inhibitor and the plant defensive mechanism against abiotic stresses

Phylogenetic analysis of Fusarium oxysporum f. sp. cubense associated with fusarium wilt of bananas from Peninsular Malaysia

Fusarium wilt of bananas caused by Fusarium oxysporum f. sp. cubense (Foc) has been known to hamper banana production. In Malaysia, most of the edible banana cultivars are susceptible to the fungal strain Foc tropical race 4 (Foc TR4). To date, molecular characterisation of Foc TR4 in this country remains elusive. Thus, this study aimed to characterise the diversity of Foc TR4 in Peninsular Malaysia based on the phylogenetic analysis of transcription elongation factor (TEF-1α) sequences. From March 2016 to December 2016, 17 isolates of Foc were isolated from nine outbreak states in Peninsular Malaysia consisting of Penang, Perak, Selangor, Negeri Sembilan, Melaka, Johor, Pahang, Kelantan and Terengganu, with disease incidence exceeding 70% in several plantations. Morphological, molecular identification using TR4 specific primers and pathogenicity assay confirmed the identity of the fungal pathogen. Pathogenicity assays indicated that the aggressiveness level varies among the isolates. Phylogenetic analyses of TEF1-α sequences showed that there was no genetic variation among the Foc isolates by clustering them into four vegetative compatibility groups (VCGs) of 01213 (TR4), 01216 (TR4), 01213/16 (TR4) and 0121 (R4). PCR amplification using VCG specific primers have further categorised 16 Foc isolates as VCG01213 and a single isolate as VCG01213/16. In addition, no correlation between TEF-1α sequences and aggressiveness of isolates could be established