Efficiency of interaction between Azotobacter SP. and arbuscular Mycorrhizal fungi for their potential to stimulate tomato plant resistance (Lycopersicon Escolentum Mill.)‎ to root rot disease

العناوين الأخرى

كفاءة التداخل بين الازوتوباكتر و فطريات المايكورايزا و جهدها في تحفيز مقاومة نبات الطماطة (Lycopersicon escolentum Mill.)‎ لمرض تعفن الجذور

مقدم أطروحة جامعية

al-Azzawi, Iyad Qahtan Wahid

مشرف أطروحة جامعية

al-Jabburi, Muna Hammudi
Abbud, Hadi Mahdi

أعضاء اللجنة

Jabir, Kamil S.
Umran, Zaydan K.
Jidiaa, Ismail A.
al-Jabburi, Kamil M.
Jarjis, Mysiri M.

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم علوم الحياة

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2010

الملخص الإنجليزي

This study was carried out during the period from 24 / 2 / 2008 until 1/ 4 / 2009 to evaluated the efficiency of interaction between Azotobacter species and arbuscular mycorrhizal fungi ( Glomus spp.

and Gigaspora spp.

) as agents for stimulating tomato plant resistance to root rot disease caused by phytopathogenic fungi ( R.

solani and F.

solani ) and improving plant growth parameters under laboratory , greenhouse and field conditions .Results showed that five Azotobacter sp.

isolates were isolated from four plant species ( tomato , corn , cucumber and muskmelon ).

Study of some biochemical characters of Azotobacter isolates showed that all these isolates were gram negative reaction and showed good to moderate growth on N-free medium containing 1% sucrose and mannitol .

The antagonistic activity of Azotobacter sp.

against R.

solani and F.

solani revealed that they varied in their ability to reduced the radial growth rate of the pathogens , and the percentage of pathogens growth inhibition .

Azotobacter isolate 4 and Azotobacter isolate 5 showed significant reduction in radial growth rate of R.

solani and F.

solani ( 3.16 , 3.03 ) cm , ( 2.0 , 1.83 ) cm respectively as compared to other three isolates ( Azotobacter isolate 1 , Azotobacter isolate 2 and Azotobacter isolate 3 ) which recorded ( 4.80 , 4.50 , 4.60 ) cm for R.

solani , and ( 2.5 , 2.60 , 2.53 ) cm for F.

solani .

Also , Azotobacter isolate 4 and Azotobacter isolate 5 appeared increment in the percentage of pathogens growth inhibition (38.56 , 41.16 ) % for R.

solani and ( 31.70 , 37.36 ) % for F.

solani as compared to Azotobacter isolate 1 , Azotobacter isolate 2 and Azotobacter isolate 3 which recorded ( 6.90 , 12.79 , 10.85 ) % and ( 14.6 , 11.2 , 13.46 ) % respectively .

The effect of three dilutions of the bacterial suspension ( 10, 15 or 20 % ) of the five isolates of Azotobacter sp.

was demonstrated on radial growth of R.

solani and F.

solani revealed that the antagonistic activity was found II to isolate type and inoculation level dependent .

Although inoculation level of all tested isolates induced significant reduction in fungal growth , but isolates ( Azotobacter isolate 4 and Azotobacter isolate 5 ) were the superior when used in all tested inoculation levels ( 10 , 15 or 20 % ) which showed significant reduction in radial growth of the two pathogens ( R.

solani and F.

solani ) , ( 3.20 , 3.13 ) cm ,( 3.06 , 3.03 ) cm , ( 3.0 , 2.9 ) cm for R.

solani , and ( 3.36 , 2.06 ) cm , ( 2.20 , 1.93 ) cm , ( 2.0 , 1.80 ) cm for F.

solani respectively .

The effect of three culture ages ( 48 , 72 , 96 hrs ) of Azotobacter sp.

on radial growth rate of R.

solani and F.

solani , showed that they were varied according to isolate type , and its age .Although ,the culture ages of all the tested isolates induced significant reduction in radial growth rate , Azotobacter isolate 5 was the best at all tested culture ages which recorded ( 2.20 , 2.13 , 2.03 ) cm for R.

solani and ( 2.66 , 2.80 , 3.03 ) cm for F.

solani .

Results of isolation and identification of arbuscular mycorrhizal fungi from rhizospheric soils of four plant species ( tomato , corn , cowpea and muskmelon ) showed that the most common AM fungi were Glomus spp.

and Gigaspora spp.

.

Glomus spp.

isolated from three plant species ; muskmelon , tomato and corn , whereas , Gigaspora spp.

was isolated from two plant species ; cowpea and corn .

Tomato seeds treated with bacterial suspension ( 1 ×106 CFU / ml ) of Azotobacter sp.

and soil with arbuscular mycorrhizal fungi and their effect on tomato seeds germination under greenhouse conditions showed that all tested factors significantly increased seeds germination , Azo.4 + Glomus and Azo.

5 + Gigaspora treatments exhibited the highest increments ( 90.0 , 83.33 ) % respectively as compared to control treatment 63.33 % .

The used of any bioagents combination not only increased seeds germination but also reduced the period required for germination .

III The efficiency of two Azotobacter isolates ( Azotobacter isolate 4 and Azotobacter isolate 5 ) and arbuscular mycorrhizal fungi ( Glomus spp.

and Gigaspora spp.

) revealed high compatible performance between Azotobacter isolates and each of Glomus spp.

and Gigaspora spp.

as manifested by the significant reduction in disease incidence ( pre and post emergency ) of tomato plants under greenhouse conditions .

Azo.

5 + R.

solani treatment showed highest decrement in disease incidence 43.33 % as compared to R.

solani treatment 83.33 % , while Azo.

5 + Gigaspora + F.

solani treatment exhibited highest decrement in disease incidence ( 29.99 ) % as compared to F.

solani treatment 86.66 % .

Efficiency of interaction between Azotobacter and AM fungi under greenhouse conditions showed that all tested bioagents separately or in combination significantly increased most tomato growth parameters ( shoot length , root length , fresh and dry weight of shoot and root , no.

of leaves and flowers / plant) .

Gigaspora + Glomus treatment was recorded first in improvement all tested tomato growth parameters which recorded 57.26 cm , (108.13 , 42.83 ) g / plant , 49.76leaves / plant , 36.70 flowers / plant , 35.46 cm , ( 40.66 , 10.60 ) g / plant respectively as compared to control treatment 26.96 cm , (66.26 , 20.40) g / plant , 24.66 leaves / plant , 12.33 flowers / plant , 17.33 cm , ( 20.56 , 5.23 ) g / plant respectively .

Impact of dual inoculation with Glomus spp.

and Gigaspora spp.

and Azotobacter sp.

on suppression tomato root rot disease caused by R.

solani and F.

solani under field conditions revealed that the tested treatments varied in their abilities in suppression disease incidence and severity .

Results showed that Azo.5 + Gigaspora + R.

solani and Gigaspora + Glomus + R.

solani treatments were the best in suppression disease incidence and severity of tomato plants which recorded ( 25.00 , 28.33 ) % , 13 , 17 respectively as compared to pathogen treatment ( R.

solani only ) which recorded ( 91.66 % , 73 ) respectively , while Azo.5 + IV Gigaspora + F.

solani treatment was the best in reducing disease incidence and severity which recorded ( 30.0 % , 16 ) respectively as compared to F.

solani only treatment which recorded 85.0 % , 72 respectively .

The effectiveness of tomato roots colonization by Glomus spp.

and Gigaspora spp.

with and without R.

solani on weight of mycorrhizal roots under field conditions showed that the treatments with R.

solani significantly reduced the percentage of roots infected with AM fungi and weight of mycorrhizal roots as compared to treatments without R.

solani .

Azo.5 + Gigaspora treatment significantly increased percentage of roots infected with AM fungi which recorded (41.11% ) as compared to control treatment 7.72 % .

Results also appeared that Azo.5 + Glomus and Azo.5 + Gigaspora treatments showed significant increment in weight of mycorrhizal roots which recorded (53.76 , 64.10 ) g /plant respectively as compared to control treatment 7.88 g / plant .

Results of the effectiveness of tomato roots colonization by Glomus spp.

and Gigaspora spp.

with and without F.

solani showed that Azo.5 + Glomus treatment with F.

solani was the best in increment the percentage of roots colonization by AM fungi and weight of mycorrhizal roots which recorded 38.83 % , 61.43 g / plant respectively as compared to control treatment 7.72 % , 7.13 g / plant respectively , treatments without F.

solani showed that Gigaspora + Glomus treatment was the best in increasing the percentage of roots colonized by AM fungi and weight of mycorrhizal roots which recorded 84.16% , 127.13 g / plant respectively .

التخصصات الرئيسية

الأحياء
النبات

الموضوعات

• البندورة

عدد الصفحات

112

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-598425