بهینه‌سازی تولید گاما‌ پلی‌گلوتامیک اسید (γ-PGA)، در باکتری Bacillus velezensis و تاثیر آن بر افزایش شاخص‌های رشدی گندم و کنترل Bipolaris sorokiniana عامل بیماری پوسیدگی معمولی ریشه گندم

نوع مقاله : مقاله پژوهشی

نویسندگان

• محسن ساسانی ¹
• مسعود احمدزاده ¹
• حسین بشارتی ²
• امیر میرزادی گوهری ³

¹ گروه گیاهپزشکی، دانشکدۀ کشاورزی، دانشگاه تهران، کرج، ایران

² بخش بیولوژی موسسه خاک و آب کشور، کرج، ایران.

³ گروه گیاهپزشکی، دانشکده کشاورزی، دانشگاه تهران، کرج، ایران

چکیده

کلیدواژه‌ها

• افزایش رشد
• کنترل بیماری
• گاما پلی گلوتامیک اسید

موضوعات

• کنترل بیولوژیک بیمایهای گیاهی

Extended Abstract

Introduction

Agriculture in the 21st century must provide food security for this growing population, which means producing more food and fiber with less labor. Therefore, agriculture in this century requires smart investment based on more efficient and environmentally friendly production methods. In modern agriculture, by using biological fertilizers and adopting appropriate strategies, it is possible to prevent nitrogen losses in the soil and reduce the efficiency of chemical fertilizers. In recent years, the development of the use of biological control agents as an alternative to chemical fungicides for the biological control of pathogens has been considered. Among them, Bacillus has an advantage over other antagonistic microorganisms due to its broad antibacterial properties, significant growth promoting effect by producing a wide range of secondary metabolites, Poly gamma glutamic acid (γ-PGA) is an anionic, biodegradable, non-toxic and hydrophilic polypeptide produced by various Bacillus species. Glutamic acid D and L are the basic units of this polymer which are created by amide bonds, numerous studies have proven that γ-PGA significantly increases plant performance and absorption of nutrients N, P, K by strengthening the absorption capacity of roots and regulating the availability of food through changing the microbial and enzymatic characteristics can also increase the ability of the biocontrol agent to control plant pathogens.

Materials and methods:

Isolation of γ-PGA producing bacteria was done from samples collected from wheat fields of Hamadan province, edible mushroom waste, palm waste and wood waste; The media culture was used for the production of γ-PGA includes: 20 grams of glucose, 20 grams of glutamic acid, 0.5 grams of KH₂PO₄, 0.1 grams of MgSo₄, 0.15 grams of CaCl₂, 2 grams of yeast extract, 0.5 grams of ZnSo₄ and 0.1 grams of MnSo₄ per litter. The γ-PGA production rate was evaluated by using cetyltrimethylammonium bromide (CTAB). Identification of bacteria using a DNA extraction kit and amplify the 16S rDNA region (Blank et al., 2018). In order to investigate the effect of bacteria and γ-PGA on the control of crown and root rot disease of wheat, cross-culture method was used in laboratory conditions and Peng et al.'s (2020) method was used in greenhouse conditions.

Results

In this research, from 180 Bacillus isolates from the samples collected from the wheat fields of Hamadan province, wastes of edible mushrooms, palm wastes and wood wastes, 9 isolates were able to produce γ-PGA with different production rates. 2 isolates were able to produce γ-PGA independently of glutamic acid. Bacillus velezensis UTB97 with a production rate of 40 g/L γ-PGA was selected as the superior producer isolate. UTB97 could prevent 65% growth of pathogenic fungi in laboratory conditions by dual culture method. Greenhouse result showed that the treatment of UTB97 and UTB97 + γ-PGA was able to control Common wheat root rot disease by 59 and 73%, respectively, compared to the control treatment, and also the treatment of UTB97 + γ-PGA was able to increase the growth index of wheat. (stem length and root dry weight), in the presence and absence of the pathogenic fungus.

Conclusion

The results of this research showed that B.Velezensis UTB97 is a powerful strain for gamma polyglutamic acid production. This strain can produce γ-PGA at the rate of 40 g/liter in optimal media culture. also use of UTB97 and γ-PGA caused the control of common crown and root rot disease of wheat and increased the growth index of wheat. Therefore, in order to increase the yield and production of wheat, simultaneous application of bacteria and γ-PGA can be promising.