[Show abstract][Hide abstract] ABSTRACT: Piriformospora indica is a basidiomyceteous fungus and able to colonize roots of many
monocotyledonous and dicotyledonous plants. This root endophyte belongs to the Sebacinales
order and can be cultivated on different media for inoculum production. P. indica shows a
potential to be used in agricultural and horticultural systems due to its benefits conferred to
the plant after root colonization. Different plant hosts show increased growth of root and
shoot, resistance against root and foliar pathogens and higher yield, but tomato as potential
host has been not studied. The influence of P.indica on tomato growth was evaluated under
different conditions of inoculation, nutrition and growth. The fungus influences positive or
negatively the tomato plants according to its inoculum density and mineral nutrient
conditions. P. indica-colonized plants can show accelerated growth during the vegetative
phase that is not obvious any more during generative development. Its potential for
application in crop production systems is discussed.
[Show abstract][Hide abstract] ABSTRACT: As Pepino mosaic virus has become a pathogen of major importance in worldwide tomato production, information is needed on possible differences between
the sensitivity of cultivars towards infection. Furthermore, it is important what hosts other than Solanaceae may be virus reservoirs and are, therefore, threats for tomato cultivation. Two PepMV isolates (PepMV-Sav, E397, a European
tomato isolate and PV-0554, a Peruvian pepino isolate) differing in their origin and virulence were used for several experiments
to investigate these issues. The response to mechanical inoculation with PepMV was studied using 25 tomato cultivars, seven
indicator plant species, and nine other possible horticultural host plants. Symptom development after infection with PepMV
was monitored and the virus was detected by DAS-ELISA and IC-RT-PCR. Garlic and broad bean were shown to be additional hosts
of PepMV depending on the virus isolate. Nicotiana benthamiana seems to be the most sensitive indicator among all tested indicator plants developing symptoms. Both PepMV isolates infected
all tested tomato cultivars. Development of disease symptoms depended on the cultivar and the virus isolate but symptoms were
not visible in all cases. None of the cultivars showed tolerance against the two isolates but two responded with a lower susceptibility
at an absorbance level of 0.2 (healthy control 0.09). It was observed that some cultivars grown hydroponically showed also
lower losses in biomass and yield. Data indicated a correlation between absorbance level in DAS-ELISA and reduction in total
No preview · Article · Apr 2011 · European Journal of Plant Pathology
[Show abstract][Hide abstract] ABSTRACT: Pepino mosaic virus (PepMV) was shown to be efficiently transmitted between tomato plants grown in a closed recirculating hydroponic system. PepMV was detected in all plant parts after transmission via contaminated nutrient solution using ELISA, immunocapture RT-PCR, RT-PCR, electron microscopy, and by inoculation to indicator plants. Detection of PepMV in nutrient solution was only possible after concentration by ultracentrifugation followed by RT-PCR. Roots tested positive for PepMV 1–3 weeks after inoculation, and subsequently a rapid spread from the roots into the young leaves and developing fruits was found within 1 week. PepMV was only occasionally detected in the older leaves. None of the infected plants showed any symptoms on fruits, leaves or other organs. Pre-infection of roots of tomato cv. Hildares with Pythium aphanidermatum significantly delayed PepMV root infections. When mechanically inoculated with PepMV at the 2–4 leaf stage, yield loss was observed in all plants. However, only plants of cv. Castle Rock recorded significant yield losses when infected via contaminated nutrient solution. Yield losses induced by infection with PepMV and/or P. aphanidermatum ranged from 0·4 up to 40% depending on experimental conditions.
[Show abstract][Hide abstract] ABSTRACT: This is the first report of Pepino mosaic virus (PepMV) occurring in tomato plants grown in plastic greenhouses in a Mediterranean city in Syria. One tomato fruit from sixty samples tested positive for this virus by DAS-ELISA. Biotest assay, RT-PCR, and sequencing confirmed the presence of PepMV. The highest sequence identity of the Syrian isolate was with the EU-tomato strains of PepMV.
No preview · Article · Apr 2010 · Phytopathologia Mediterranea
[Show abstract][Hide abstract] ABSTRACT: Piriformospora indica is a root endophytic fungus with plant-promoting properties in numerous plant species and induces resistance against root and shoot pathogens in barley, wheat, and Arabidopsis. A study over several years showed that the endophyte P. indica colonised the roots of the most consumed vegetable crop tomato. P. indica improved the growth of tomato resulting in increased biomass of leaves by up to 20%. Limitation of disease severity caused by Verticillium dahliae by more than 30% was observed on tomato plants colonised by the endophyte. Further experiments were carried out in hydroponic cultures which are commonly used for the indoor production of tomatoes in central Europe. After adaptation of inoculation techniques (inoculum density, plant stage), it was shown that P. indica influences the concentration of Pepino mosaic virus in tomato shoots. The outcome of the interaction seems to be affected by light intensity. Most importantly, the endophyte increases tomato fruit biomass in hydroponic culture concerning fresh weight (up to 100%) and dry matter content (up to 20%). Hence, P. indica represents a suitable growth promoting endophyte for tomato which can be applied in production systems of this important vegetable plant not only in soil, but also in hydroponic cultures.
[Show abstract][Hide abstract] ABSTRACT: Pepino mosaic virus (PepMV) is nowadays known to infect tomato severely. At the moment the virus can only be controlled by comprehensive disinfection and care in the greenhouse. Therefore, this project aimed to test the fungi as biological agents to confine the disease. Pythium aphanidermatum, Pythium oligandrum, and Piriformospora indica were selected because they are known to either promote plant growth or delay infection and distribution of PepMV, as found after pre-infection with P. aphanidermatum. Tomatoes cv. Hildares were grown in nutrient solution in a greenhouse for 84 days. Plants were inoculated with a suspension of spores and mycelium of the three fungi. Twenty days later, leaves of 50% of the plants were inoculated mechanically with PepMV leave homogenates containing the Frenchisolate E 397/1. Success of infection was confirmed and quantified with DAS-ELISA. Infection of the three fungi was confirmed by light microscopy. Expression of several genes involved in plant defence mechanisms was analyzed. Analyses of tomato inoculated only with P. indica resulted in a significant enhancement of growth and fruit setting, for the first time shown in nutrient solution. The two other fungi did not affect the growth significantly. However, all fungi promoted the distribution of PepMV in the tomato shoot organs. No correlation was found between gene expression patterns and spread of PepMV. But the defence-related genes selected were always induced significantly when tomato was infected by both P. indica and PepMV. Mechanisms leading to the higher susceptibility of tomatoes against PepMV in the presence of a fungus are not clear and must be investigated in further experiments.
No preview · Article · Mar 2009 · Acta horticulturae