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Plant defensins are small, basic peptides that have a characteristic three-dimensional folding pattern which is stabilized by four disulfide bridges. We show here that Arabidopsis contains in addition to the proper plant defensins a group of 9 plant defensin-like (PdfL) genes. They are all expressed at low levels while GUS fusions of the promoters showed expression in most tissues with only minor differences. We produced two of the encoded peptides in E. coli and tested the antimicrobial activity in vitro. Both were highly active against fungi but had lower activity against bacteria. At higher concentrations hyperbranching and swollen tips, which are indicative of antimicrobial activity, were induced in Fusarium graminearum by both peptides. Overexpression lines for most PdfL genes were produced using the 35S CaMV promoter to study their possible in planta function. With the exception of PdfL4.1 these lines had enhanced resistance against F. oxysporum. All PDFL peptides were also transiently expressed in Nicotiana benthamiana leaves with agroinfiltration using the pPZP3425 vector. In case of PDFL1.4 this resulted in complete death of the infiltrated tissues after 7 days. All other PDFLs resulted only in various degrees of small necrotic lesions. In conclusion, our results show that at least some of the PdfL genes could function in plant resistance.

Leaf rust disease affects the wheat crop in several countries around the globe and it can influence the grain yield and its components. This research was carried out using 35 wheat genotypes during the growing season of 2016-2017 with 3 replications by RCBD under contrasting rust disease regimes. The statistical techniques used for the multivariate analyses include the calculations of correlations, principal components and clusters. The data about various physiological traits, grain yield components and disease severity were recorded under high disease pressure and maximum disease control conditions. Correlation analysis showed highly significant positive relationship of disease severity with relative membrane permeability but negative association with chlorophyll contents in the flag leaf and some yield attributes. In control conditions, the relative water content exhibited a highly significant positive relationship with the flag leaf area while highly significant negative relationship was observed with specific flag leaf weigh under disease condition. Principal component analysis demonstrated that first 4 PCs having eigenvalue >1 elucidated 73.578% and 82.80% of the total variation under diseased and control conditions respectively. Cluster analysis grouped 35 wheat genotypes among four different clusters. The members of cluster 1 revealed the maximum disease severity under control condition, but the disease severity was maximum for cluster 4 under disease condition. Scatter plot explained that, not a single cluster showed clear separation. The tree diagram also indicated that diversity in different disease conditions is controlled by genotypes. The results concluded that this genetic diversity could be helpful to the researchers and breeders for future objectives to enhance the food production and leaf resistance in bread wheat. [ABSTRACT FROM AUTHOR]

Tomato crop is affected with several diseases that lead to decreased yield every year. Among those diseases, tomato wilt is the most significant disease caused by soil borne pathogens i.e. Fusarium solani, Fusarium oxysporum, and Verticillium spp. In the present study, survey was conducted in tomato growing areas of Punjab. Pathogens associated with plants were Fusarium oxysporum, Alternaria solani, parasitic nematodes, Pythium, Verticillium dahliae and mosaic virus. The survey was conducted at three different stages of plant development and disease incidence and severity were correlated with environmental factors. This survey was conducted for consecutive two years (2017-18:2018-19). It was shown that fusarium wilt can infect all growing stages (nursery, flowering and fruiting) of tomato plant. Moreover, high temperature and high humidity favored disease prevalence. Huge damage was witnessed due to high temperature and relative humidity up to a certain limit. Furthermore, it was also observed that alternaria blight, verticillium wilt, nematodes and mosaic virus also attacked at different growth stages to different extents along with fusarium wilt. Plants were more vulnerable at fruiting stage to all diseases. The present study will be helpful for devising a proper management strategy for fusarium wilt disease in tomato crop. [ABSTRACT FROM AUTHOR]

Brown spot disease (Bipolarisoryzae) is increasing threat to global food security in the world as well as the most damaging disease of rice crop in Pakistan. In September 2017, a field survey was conducted in four rice-growing districts of Punjab namely (Faisalabad, Hafizabad, Sheikhupura and Lahore) and diseased samples were collected from different fields of rice showing disease symptoms. The results showed that Ninety-seven fields of rice were surveyed and 62 were found infected with disease. Disease prevalence was highest in district Sheikhupura 84%, followed by Lahore, Hafizabadand, Faisalabad with 80%, 60% and 53% respectively. The risk of disease incidence was highest in district Sheikhupura and Lahore82% in Super Basmati, 74% in KSK-282 followed by Faisalabad and Hafizabad71% in Super basmati, 60% in Super rice respectively. The severity rate was the highest in district Lahore at KotPindiDass 88%in Super rice, but the minimum was observed atShamke road 46% in PK 386. It is concluded that, the disease incidence and severity level of B. oryzae was higher in fields of district Sheikhupura in Punjab, Pakistan. [ABSTRACT FROM AUTHOR]

Trogoderma granarium (Everts) is one of the world's most destructive pests of cereals, oilseed, malting, and other foodstuffs. Current studies were aimed to investigate the effect of essential oils of two different medicinal plants (Dhatura alba and Calotropis procera) against two different strains of T. granarium. Plant extracts were obtained by Rotary Shaker apparatus by using acetone as solvent. Four different concentrations 5%, 10%, 15% and 20% were prepared by diluting in acetone. The data regarding mortality, growth regulation and repellency of T. granarium was observed. Repellency of plant extracts was tested using area preference method while for the growth regulatory potential of plant extracts, the adults insects were released in wheat grains treated with different concentrations of plant extracts. All the experiments were carried out in an incubator at 30±2°C and 65±5% R.H using Completely Randomized Design (CRD). The results for repellency remained more significant for C. procera extract as compared to D. alba. While for growth the C. procera showed more significant differences. In case of mortality both D. alba and C. procera were found equally effective against T. granarium. [ABSTRACT FROM AUTHOR]

Plant WRKY transcription factors play a vital role in abiotic stress tolerance and regulation of plant defense responses. This study examined AtWRKY11 and AtWRKY17 expression under ABA, salt, and osmotic stress at different developmental stages in Arabidopsis . We used reverse transcriptase PCR, quantitative real-time PCR, and promoter:GUS lines to analyze expression. Both genes were upregulated in response to abiotic stress. Next, we applied the same stressors to seedlings of T-DNA insertion wrky11 and 17 knock-out mutants (single and double). Under stress, the mutants exhibited slower germination and compromised root growth compared with the wild type. In most cases, double-mutant seedlings were more affected than single mutants. These results suggest that wrky11 and wrky17 are not strictly limited to plant defense responses but are also involved in conferring stress tolerance. [ABSTRACT FROM AUTHOR]