Assessing synergism of combined applications of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> and <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis> to control blast and bacterial leaf blight of rice     

Prashant P. Jambhulkar  Pratibha Sharma  Raja Manokaran  Dilip K. Lakshman  Pramod Rokadia  Nitiprasad Jambhulkar 《European journal of plant pathology / European Foundation for Plant Pathology》2018,150(3):747-758

Laimaphelenchus suberensis sp. nov. obtained from declining Quercus suber trees of Herdade da Gouveia de Baixo, Alentejo, Portugal, is described and illustrated based on morphological, biometrical and molecular characters. The diagnosis of Laimaphelenchus species has been commonly based on the presence or absence of a vulval flap and on the shape structure of the tail tip. The species described here has been included in the Laimaphelenchus group without vulval flap, and can be distinguished from morphologically similar species by its tail tip shape structure that has a stalk-like terminus and three diffuse tubercles with 4–6 finger-like protrusions. For the molecular analyses, the mitochondrial DNA region from the cytochrome oxidase subunit I (mtCOI), the D2-D3 expansion segments of the large subunit (LSU) and small subunit (SSU) of rRNA gene were amplified and sequenced. Sequences of L. suberensis sp. nov. clustered separately from all Laimaphelenchus spp. with available sequences in Genbank, confirming its identification as a new species. This is the second report of the genus Laimaphelenchus in Portugal, associated with Q. suber: L. heidelbergi and L. suberensis sp. nov.  相似文献   

Development of Superhydrophobic Microfibers for Bandage Coatings     

T. S. Gokul Raja  K. Jeyasubramanian  M. Indhumathy 《Fibers and Polymers》2018,19(6):1207-1218

In this research work, a fabricated composite fiber is proposed to protect wound surfaces from infectious organisms present in water. The composite fiber comprising PMMA, ZnO, and zinc stearate was developed using an electrospinning technique. The fiber surface was scientifically studied using scanning electron microscope, Energy dispersive analysis of X-rays, powder X-ray diffraction analysis and Fourier transform Infra-Red analysis. The pores present in between perpendicularly aligned fibers serves as an excellent medium for vapor transport to a wound surface. The maximum water contact angle of the developed fiber surface was approximately 151 degrees. A commercial cotton bandage after coated with this composite layer behaves as a perfect barrier to the entry of infectious water towards the wound. The pores in the fiber surface support rich supply of environmental oxygen and transport of exudate vapor from the wound. This fiber when coated over a cotton bandage cloth on one side served as an excellent wound protecting bandage against the penetration of external microbial water and also it admits the air, water vapor etc., towards the interior. Water penetration ability of hydrophilic cotton bandage and the water arresting ability of superhydrophobic fiber coated bandage were evaluated using a facile technique. Furthermore, antimicrobial activity of test samples was evaluated against gram positive and gram negative microorganism. Also, a bacterial infiltration test supports the blocking capability of superhydrophobic fiber to water-borne bacteria. The results obtained through this experiment may be used in future as wound healing bandages in an efficient manner.  相似文献   

Barley yield losses due to defoliation of upper three leaves either healthy or infected at boot stage by <Emphasis Type="Italic">Pyrenophora teres</Emphasis> f. <Emphasis Type="Italic">teres</Emphasis>     

Rajaâ Jebbouj  Brahim El Yousfi 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(2):303-315

This paper evaluates, in the greenhouse and under natural conditions, barley yield losses due to defoliation treatments of the upper three leaves either healthy or infected at the boot stage by Pyrenophora teres f. teres. Defoliation was assumed as a loss of a similar leaf area caused by net blotch disease severity of 100%. Contribution to grain yield was defined herein as a difference between defoliation treatments and a treatment where plants lost all their upper three leaves. In contrast, yield losses referred to differences in yield between defoliations and the control. In the greenhouse, removal of the antepenultimate leaf did not affect any yield component. For main stems, defoliating upper three leaves reduced grain yield by 30% and this was mainly due to flag leaf removal. These losses were similar to those induced by net blotch disease under natural conditions, but were of 42% for all tillers. Grain yield losses due to disease severity were not equivalent to the defoliation effect of a similar healthy leaf area. On the other hand and for a significant contribution to grain yield, flag leaf was dependent on the presence of the other two leaves. Inoculation and defoliation of 21 cultivars induced similar grain yield losses of 32%. However, biotic stress reduced by 40% the contribution of their upper three leaves. Under field conditions, yield losses were not significant until barley plants lost more than one upper leaf and flag leaf contribution was equivalent to that of the remaining leaves. Characteristic roots, defined as leaf coefficients for plant performance, were 0.13, 0.06 and 0.01 for the flag, penultimate and antepenultimate leaves, respectively. Because antepenultimate leaves become trivial at the boot stage, we propose that coefficients of the remaining leaves should be used when modelling yield losses due to barley foliar diseases.  相似文献   

Experimental horizontal transmission of Enterocytozoon hepatopenaei in post‐larvae of whiteleg shrimp,Litopenaeus vannamei     

Kesavan Karthikeyan  Raja Sudhakaran 《Journal of fish diseases》2019,42(3):397-404

Enterocytozoon hepatopenaei (EHP) is a microsporidian parasite that causes hepatopancreatic microsporidiosis (HPM) in penaeid shrimp. HPM was observed in several countries, including Thailand and India; it has become a prominent pathogen in shrimp culture. Based on observations on EHP infection in the wild, the route of transmission has been hypothesized. Identification of artificial EHP infection procedures can facilitate our understanding of EHP transmission. Experimental transmission of EHP was attempted using the immersion and oral infections of infection. In the immersion mode, post‐larvae (PL) were exposed to an EHP tissue homogenate (0.2%) by immersion for 48 hr. Experimental samples were collected at various time points, and infection was confirmed using polymerase chain reaction, haematoxylin and eosin staining, transmission electron microscopy and modified trichrome staining. All test results revealed successful EHP transmission. Similar results were obtained through oral infection (oral infection). Innate immune gene expression patterns during infection were analysed; prophenoloxidase, crustin and superoxide dismutase were upregulated at 6, 6 and 48 hr post‐challenge, respectively. Experimental infection procedures facilitate the development of diagnostic and prevention strategies. This is the first study demonstrating the experimental transmission of EHP in shrimp PL.  相似文献   

Quick report on prevalence of shrimp microsporidian parasite Enterocytozoon hepatopenaei in India          下载免费PDF全文

Karthikeyan Kesavan  Ravi Mani  Itami Toshiaki  Raja Sudhakaran 《Aquaculture Research》2017,48(7):3980-3984

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Evaluating smallholder farmers’ demand for rice variety attributes in Nepal     

Uttam Khanal  Ananda Adhikari  Clevo Wilson 《Journal of Crop Improvement》2017,31(3):438-452

Despite the release of many modern varieties of rice (Oryza sativa), farmers in Nepal have been cultivating relatively few rice varieties. The objective of this study is to estimate farmers’ demand for rice variety attributes and to identify the factors that influence their decision regarding varietal choice. Yield increase is considered jointly with other attributes, such as cooking and eating quality, drought tolerance, and maturity period. Choice experiments were conducted and results showed that there was significant demand from farming households for yield increase, improvement in cooking and eating quality, tolerant to drought, and short maturing varieties. The choice data were analyzed using a multinomial and random parameter logit model. From a policy perspective, results showed that for broader adoption of crop varieties, variety development programs should give priority to aforementioned attributes rather than solely on increased crop productivity.  相似文献   

The host background of rice influences the resistance expression of a three genes pyramid (xa5 + xa13 + Xa21) to bacterial blight (Xanthomonas oryzae pv. oryzae) pathotypes of Indian mainland and Bay islands          下载免费PDF全文

Krishnan Sakthivel  Raj K. Gautam  Kaari Manigundan  Reena Singh  Jegadeesan Ramalingam  Gouri S. Laha  Aundy Kumar  Rethinasamy Velazhahan 《Plant Breeding》2017,136(3):357-364

Bacterial blight (BB) is a major disease of rice for which host resistance is the only effective solution. The three genes pyramid xa5 + xa13 + Xa21 is recently the most utilized combination for developing resistant varieties through marker‐assisted breeding. Our study was carried out to elicit the detailed response of twenty lines possessing these three genes in five genetic backgrounds to twelve diverse BB pathotypes in India. The lines developed from ADT 47 variety showed incomplete resistance to most of the pathotypes, whereas susceptibility varied from 8.3% to 16.6% in ADT 43 and IR24, respectively. However, in IMP ASD16/60 and Improved Samba Mahsuri, complete resistance against all pathotypes was observed. The overall results confirmed that genetic background plays crucial role for the effective expression of xa5 + xa13 + Xa21 combination. Molecular studies did not reveal correlation between origin of pathotypes and their virulence potential. It is suggested to deploy Improved Samba Mahsuri, IMP ASD 16/60 and AD1306 varieties in the bacterial blight prone areas or use them as donors for realizing wider and durable resistance.  相似文献   

Improving sweet sorghum for enhanced juice traits and biomass     

Ananda Y. Bandara  Dilooshi K. Weerasooriya  Dereje D. Gobena  Daniel J. Hopper  Tesfaye T. Tesso  Christopher R. Little 《Plant Breeding》2020,139(1):131-140

Sweet sorghum (Sorghum bicolor [L.] Moench) is a prospective bioethanol feedstock source. Four high-biomass and sweet sorghum male lines and three grain sorghum female lines were intercrossed using Design II mating. Parents and hybrids were evaluated to (a) identify genetic sources to improve biofuel traits, and (b) determine the inheritance of biofuel and morpho-agronomic traits. Total soluble sugars (TSS) per plant were determined using juice weight (JW) and Brix (°Bx). Plant height (PH), biomass (BM) and stalk diameter (SD) were also measured. Mean hybrid performance for PH, JW, TSS and BM was higher than the male parent means. Three male parents exhibited positive and significant general combining ability (GCA) for at least three traits. Among males, PI185672 showed the highest GCA for PH, °Bx and BM, while No. 08 exhibited the greatest GCA for JW and TSS. Most hybrids exhibited overdominance-driven high-parent heterosis for all traits except SD. Trait broad-sense heritability ranged from 0.71 (BM) to 0.93 (PH). Results revealed that biofuel traits could be substantially improved through breeding, which will contribute to enhanced bioethanol production.  相似文献   

Development of a large population of activation-tagged mutants in an elite indica rice variety     

Vamsee Raja Kota  Sivakrishna Rao Gundra  Dashavantha Reddy Vudem  Bharadwaja Kirti Pulugurtha  Venkateswara Rao Khareedu 《Plant Breeding》2020,139(2):328-343

In this study, we have generated more than 12,000 activation-tagged mutants in a high-yielding indica rice variety, 'BPT 5204', employing maize Ac/Ds system. Different transgenic plants obtained were analysed based on expression patterns of green fluorescence protein (GFP), red fluorescence protein (RFP), herbicide (Basta) tolerance and molecular analyses. T₁ seeds of pSQ5 and pSQ5-bar transgenics, when germinated separately on hygromycin (50 mg/L) and phosphinothricin (5 mg/L) containing medium, revealed a segregation of 3 tolerant : 1 susceptible plants. The germinal transposition frequency of Ds element in different T₂ progeny of rice plants was found to be about 18.0%. Different stable tagged mutants exhibited marked increases in plant height, number of tillers, leaf size, panicle size, seed size and number of grains per plant. The overall results indicate that the genes associated with these traits are upregulated by the enhancer element in activation-tagged mutants. As such, the various tagged mutant lines appear promising and serve as a valuable genetic resource for identification of key genes determining different agronomic traits of rice.  相似文献   

Effect of Nutrient Application on Growth,Metabolic and Enzymatic Activities of Rice Seedlings During Flooding Stress and Subsequent Re‐Aeration          下载免费PDF全文

B. Lal  L. Rath  D. Haldar  B. B. Panda  R. Raja  M. Shahid  R. Tripathi  P. Bhattacharyya  S. Mohanty  A. K. Nayak 《Journal of Agronomy and Crop Science》2015,201(2):138-151

The impact of submergence on the allometry, changes in metabolic activities and antioxidant enzymes during oxidative stress in four Indica rice varieties namely IR‐20, IR‐64 Sub1, Swarna Sub1 and Savitri Sub1 was studied. The differential response of flooding under clear and turbid water with different nutrient application schedules was also examined during and after 12 days of complete submergence. Submergence substantially reduced allometric parameters and the activities of antioxidant enzymes but increased the % change in chlorophyll, soluble sugars and malondialdehyde (MDA) across cultivars with drastic effects on IR‐20. Turbid water resulted in higher leaf senescence, lodging, higher depletion of chlorophyll and soluble sugars because of poor light transmission. Pre‐submergence N application resulted in higher lodging, leaf senescence and higher MDA level but depletion of chlorophyll and NSC leading to higher % change over prior to submergence. Basal P application reduced the senescence and lodging, whereas increased the antioxidant enzyme activities. Foliar spray of post‐submergence N with basal P improved the retention and regain of chlorophyll, soluble sugar and increased the dry matter, leaf area and root shoot ratio. Crop establishment could therefore be enhanced in areas where untimely flooding is anticipated by applying basal P and foliar spray of urea after desubmergence.  相似文献