Wyniki wyszukiwania - Biblioteka Nauki

1

The effects of beta-amino-butyric acid on resistance of cucumber against root-knot nemetode, Meloidogyne javanica

100%

Sahebani N. , Hadavi N. S. , Zade F. O.

Acta Physiologiae Plantarum

|

2011

|

tom 33

|

nr 2

EN

In this study, the effects of b-amino-butyric acid (BABA) on root-knot nematode(Meloidogyne javanica) infection of cucumber and accumulation of total phenolic compounds, hydrogen peroxide and activity of some enzymes related to plant defense mechanisms, i.e., guaiacol peroxidase (GPOX), polyphenol oxidase (PPO), catalase (CAT) in cucumber roots infected with nematode were investigated. Results of this study show that treating the cucumber seedlings with the above elicitor significantly reduces the nematode infection level (the nematode galls, number of egg masses per plant and number of eggs per individual egg mass) compared to control. Additionally, treatment of cucumber roots by BABA and BABA + nematode, significantly increased peroxidase, polyphenol oxidase and catalase activities in root tissues, 1 day after nematode inoculation in comparison to nematode inoculated plants as control and sterile water-treated plants. Enzyme activities reached to a maximum level at 4, 4 and 3 days after nematode inoculation, respectively. Additionally, the amount of H₂O₂, a product of oxidative stress, was significantly increased in the BABA and BABA + nematode treatments in comparison to control. Such increases have occurred in two phases and maximum levels of it were observed at 5 days after inoculation. Inoculation of cucumber plants by BABA also significantly increased accumulation of total phenol in comparison to control and maximum level of it was observed at 7 days after nematode inoculation. The results suggest that the inhibitory effect of BABA on the root-knot nematode (M. javanica) may be related to its ability to enhance defense responses in the cucumber roots.

2

Control of postharvest decay of apple fruit with Trichoderma virens isolates and induction of defense responses

100%

Bordbar F. T. , Etebarian H. R. , Sahebani N. , Rohani H.

Journal of Plant Protection Research

|

2010

|

tom 50

|

nr 2

146-152

EN

The biocontrol activity of two isolates of Trichoderma virens against blue mould of apple fruits caused by Penicillium expansum and their ability to induce biochemical defense responses in apple tissue were investigated. Apple fruit (Malus domestica) wounds were inoculated with 20μl antagonist suspension (107 conidia/ml) of T. virens and 4 h later with 20 μl of conidial suspension of P. expansum (105 conidia/ml). The apples were then incubated at 20°C for 8 days. Lesion diameters were measured 4 and 8 days after inoculation with the pathogen. Two isolates of T. virens were effective in controlling decay of apple fruits caused by P. expansum. Six days after treatment peroxidase activity increased by more than three-fold in apple treated fruit in combination of antagonist and pathogen, in comparison with in wounded, non-inoculated control tissue. Catalase (CAT) activity increased in inoculated fruits in combination of T. virens and P. expansum in comparison with healthy control at all days and maximum activity level was noted at 6 days after inoculation. The results indicated that T6 and T8 isolates of T. virens caused the increase in β-1,3-glucanase activity that reached maximum levels 4 and 6 days after inoculation with pathogen, respectively. The increase in β-1,3-glucanase activity was triggered by wounding although the level of increase was markedly lower than detected in treated fruits. Phenolic compounds accumulation showed the highest levels 2-4 days after inoculation and then decreased. The ability of T. virens to increase the activity of peroxidase, catalase, β-1,3-glucanase and levels of phenolic compounds may be one of mechanisms responsible for its biocontrol activity.

PL

Badano aktywność biologicznego zwalczania dwóch izolatów Trichoderma virens w ograniczaniu niebieskiej pleśni wywoływanej przez Penicillium expansum oraz ich zdolność indukowania biochemicznych reakcji obronnych w tkance jabłek. Rany na jabłkach (Malus dimestica) inokulowano z 20 μl zawiesiny konidiów (107 konidiów/ml) T. virens, a po następnych 4 godzinach z 20 μl zawiesiny konidiów P. expansum (105 konidiów/ml), po czym jabłka inokulowano w 20°C w ciągu 8 dni. Po 4 i 8 dniach, po inokulacji patogenem, mierzono średnicę ran. Dwa izobaty T. virens wykazywały efektywność w zwalczaniu gnicia jabłek wywoływanego przez P. expansum. Sześć dni po tym zabiegu aktywność peroksydazy wzrastała ponad trzykrotnie w jabłkach traktowanych w kombinacji z antagonistą i patogenem, w porównaniu do nieuszkodzonej, nie inokulowanej tkanki owoców w kombinacji kontrolnej. Aktywność katalazy (CAT) wzrastała w inokulowanych owocach w kombinacji z T. virens i P. expansum we wszystkich odmianach w porównaniu do zdrowej kontroli, a maksymalny poziom aktywności stwierdzono 6 dni po inokulacji. Uzyskane wyniki wykazały, że izobaty T6 i T8 T. virens powodowały wzrost aktywności β-1,3- glukazyny, która osiągała odpowiednio maksymalne poziomy po 4 i 6 dniach po inokulacji patogenem. Zranienie stymulowało wzrost aktywności β-1,3-glukazyny, chociaż poziom wzrostu był znacznie niższy niż wykryty w owocach traktowanych. Akumulacja związków fenolowych była na najwyższym poziomie 2-4 dni po inokulacji i później zmniejszała się. Zdolność T. virens do zwiększania aktywności peroksydazy, katalazy, β-1,3-glukazyny oraz poziomu związków fenolowych może być jednym z mechanizmów odpowiedzialnych za procesy biologicznego zwalczania.

3

Induction of systemic resistance and defense-related enzymes in tomato plants using Pseudomonas fluorescens CHAO and salicylic acid against root-knot nematode Meloidogyne javanica

88%

Nikoo F. S. , Sahebani N. , Aminian H. , Mokhtarnejad L. , Ghaderi R.

|

tom 54

|

nr 4

EN

Root-knot nematodes (Meloidogyne spp.) are the most economically important group of plant parasitic nematodes on many crops worldwide. Resistance-based management is considered as one of the most sound and effective strategies against these pathogens. Plant-mediated systemic resistance against the M. javanica in tomato cv. CALJN3 was triggered using salicylic acid (SA) and Pseudomonas fluorescens CHAO as elicitors. The effect of each elicitor was assayed by (1) the calculation of nematode indices including the number of nematode galls, egg masses and eggs/egg mass; (2) the analysis of changes in the concentration of reactive oxygen species (ROS); and (3) monitoring the activities of their scavenging enzymes viz. superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT). The results indicated that SA/bacterial elicitors induced the removal of high concentrations of the toxic ROS via an increase in the activity of their scavenging antioxidant enzymes, especially that of catalase. Moreover, pre- or post-treatment application of the elicitors significantly reduced the number of galls, egg masses or eggs of M. javanica in infected tomato plants as compared to the control. The results of the present study support the involvement of the elicitor-induced ROS and related scavenging enzymes for stimulating plant defense reactions in a moderately resistant tomato challenged with M. javanica.