A new interspecific pear cultivar Yutaka: highly resistant to the two major diseases scab and black spot on Asian pears

Phytoplasma suspected symptoms of little leaf, flat stem, witches’ broom and leaf yellowing were recorded on the four legume species, cowpea (Vigna unguiculata (L.) Walp.), pigeon pea (Cajanus cajan (L.) Millsp.), lentil (Lens culinaris Medikus) and mung bean (Vigna radiata (L.) Wilczek) in the states of Delhi, Uttar Pradesh (UP) and Kerala from 2014 to 2016. DNA specific fragments of approximately 1.3 kb were amplified from symptomatic samples of cowpea, pigeon pea, lentil and mung bean in nested PCR assays by using two sets of universal phytoplasma nested specific primers P1/P7 followed by 3Far/3Rev. No DNA amplifications were observed in any of the non-symptomatic legume samples with same primer pairs. Pair wise sequence comparison, phylogeny and virtual RFLP analysis of 16S rDNA sequences of the four legume species confirmed the association of four different groups and subgroups of phytoplasmas in the present study. The mung bean witches’ broom at Delhi was identified to be associated with strain related to ‘Ca. P. aurantifolia’ (16SrII-D), pigeon pea little leaf at Faizabad, UP with strain related to ‘Ca. P. phoenicium’ (16SrIX-C), lentil witches’ broom at Faizabad, UP with ‘Ca. P. trifolii’ (16SrVI-D) and cow pea flat stem disease at Kerala with ‘Ca. P. cynodontis’ (16SrXIV-A). Association of ‘Ca. P. cynodontis' (16SrXIV-A) infecting cowpea, ‘Ca. P. trifolii’ (16SrVI-D) in lentil and phytoplasmas strain related to ‘Ca. P. phoenicium’ (16SrIX-C) infecting pigeon pea are the new reports to the world.     

Searching by Differential Display for New Genes Implicated in Induced Disease Resistance of Cucumber Treated with Acibenzolar-S-methyl

Acibenzolar-S-methyl (ASM) is a chemical activator of systemic disease resistance in plants. In this study, we used differential display to identify ASM-inducible defense response genes involved in induced disease resistance. As a result, we cloned three ASM-inducible genes from cucumber, encoding a chitinase, a putative protein disulfide isomerase and a putative mitochondrial-protein-like protein. Expression of these genes was induced within 24 hr after treatment of cucumber leaves with ASM. These results suggest that differential display is a useful tool for understanding the mode of action of ASM and defense responses. Received 6 September 2000/ Accepted in revised form 11 April 2001     

Occurrence of boscalid resistance in cucumber powdery mildew in Japan and molecular characterization of the iron–sulfur protein of succinate dehydrogenase of the causal fungus

A total of 74 mass isolates of cucumber powdery mildew fungus (Podosphaera xanthii) were collected from commercial greenhouses with a history of boscalid use in Ibaraki Prefecture, Japan, and tested in a leaf disk assay for their sensitivity to boscalid. The mildew development of 40 of 74 isolates and five sensitive reference isolates on the disks was completely suppressed at 5 μg boscalid/ml. The minimum inhibitory concentrations (MIC) for the remaining 34 isolates were 50 μg/ml or higher, and 21 of these isolates also grew well at 500 μg/ml. Six single-spore isolates were resistant to boscalid with MIC values higher than 500 μg/ml; four of these were moderately resistant (MR), and two were very highly resistant (VHR) isolates. The growth of MR isolates was almost completely suppressed at 500 μg/ml, whereas two VHR isolates grew vigorously at 500 μg/ml. In foliar inoculation tests of potted cucumber plants, the efficacy of boscalid (500 μg/ml) against both MR and VHR isolates was very low. Partial DNA fragment of the iron–sulphur protein subunit (SdhB) gene of succinate dehydrogenase was PCR-amplified from five sensitive and five resistant isolates and directly sequenced, revealing that VHR isolates possess a substitution from a highly conserved histidine (CAT) to tyrosine (TAT) in a third cysteine-rich center of a putative SdhB, whereas MR isolates so far have not been found to have such substitution in SdhB.     

Suppressive effect of abscisic acid on systemic acquired resistance in tobacco plants

Recent studies have indicated that the phytohormone abscisic acid (ABA), induced in response to a variety of environmental stresses, plays an important role in modulating diverse plant–pathogen interactions. In Arabidopsis thaliana, we previously clarified that ABA suppressed the induction of systemic acquired resistance (SAR), a plant defense system induced by pathogen infection through salicylic acid (SA) accumulation. We investigated the generality of this suppressive effect by ABA on SAR using tobacco plants. For SAR induction, we used 1,2-benzisothiazole-3(2H)-one 1,1-dioxide (BIT) and benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH) that activate upstream and downstream of SA in the SAR signaling pathway, respectively. Wild-type tobacco plants treated with BIT or BTH exhibited enhanced disease resistance against Tobacco mosaic virus (TMV) and tobacco wildfire bacterium, Pseudomonas syringae pv. tabaci (Pst), however, which was suppressed by pretreatment of plants with ABA. Pretreatment with ABA also suppressed the expression of SAR-marker genes by BIT and BTH, indicating that ABA suppressed the induction of SAR. ABA suppressed BTH-induced disease resistance and pathogenesis-related (PR) gene expression in NahG-transgenic plants that are unable to accumulate SA. The accumulation of SA in wild-type plants after BIT treatment was also suppressed by pretreatment with ABA. These data suggest that ABA suppresses both upstream and downstream of SA in the SAR signaling pathway in tobacco.     

First report of plum pox virus infecting Japanese apricot (<Emphasis Type="Italic">Prunus mume</Emphasis> Sieb. et Zucc.) in Japan

For the first time, plum pox virus (PPV) has been detected in commercial Japanese apricot (Prunus mume) trees in Tokyo, Japan. These trees had ringspot or mottle on leaves, color breaking of petals and, occasionally, mild ringspots and malformation on fruits. The virus was identified based on the morphology of virus particles, serology, and RT-PCR. The amplified nucleotide fragment shared 100% identity with a partial coat protein gene of PPV-D isolates.     

Effect of p-chlorophenyl dimethyl urea on the degradation of chlorophyll in detached rice leaf in the light

It was observed previously that, when a fully developed leaf of the rice plant (Oryza sativa) was detached and kept in the light, more rapid loss of chlorophyll took place than in the dark during their incubation. Since this had been considered to be associated with photosynthesis, the effects of CMU (p-chlorophenyl dimethyl urea) and other compounds on the degradation of chlorophyll were studied. CMU had a significant effect in retarding the degradation of chlorophyll in the light irrespective of the presence of sucrose, whereas monoiodo acetic acid was far less effective. The degradation of chlorophyll was greatly promoted, especially in the light, when a detached leaf was kept in oxygen gas, but was delayed in nitrogen gas.

Electron microscopic observation showed that grana fret-work system and chlorophyll membrane were maintained in a healthy condition for the first few days during treatment with CMU. But they were completely degraded without CMU, and the disorganization of chloroplasts was accompanied by a rapid degradation of chlorophyll. It was assumed that oxygen evolved in photosynthetic reaction causes light-induced degradation of chlorophyll, and CMU represses degradation by inhibiting oxygen evolution in the light reaction of photosynthesis. A suggestion was made as to the scheme of light-induced degradation of chlorophyll relative to photosynthetic reaction and the mode of action of CMU.     

The influence of increased water temperature on the duration of spermatogenesis in a neotropical fish,Astyanax altiparanae (Characiformes,Characidae)

Fish Physiology and Biochemistry - In view of the established climate change scenario and the consequent changes in global temperature, it is essential to study its effects on animal...     

Elevation of serum surfactant protein-A with exacerbation in canine eosinophilic pneumonia

A 7-year-old female spayed Labrador Retriever was admitted to our hospital, because ofcough with sputum. She was diagnosed as having canine eosinophilic pneumonia (CEP) basedon blood eosinophilia, bronchial pattern and infiltrative shadow observed on thoracicradiography, bronchiolar obstruction and air-space consolidation predominantly affectingthe right caudal lung lobe, as revealed by computed tomography (CT), predominanteosinophils in CT-guided fine needle aspiration and the clinical course. She exhibited agood response to steroid therapy, and the cough disappeared. The serum surfactant protein(SP)-A level increased with the aggravated symptom and decreased markedly with improvementcompared with the C-reactive protein level and the number of eosinophils. We propose thatserum SP-A level is a good biomarker in CEP.