Influence of enhanced malate dehydrogenase expression by alfalfa on diversity of rhizobacteria and soil nutrient availability

نویسندگان

  • Mesfin Tesfaye
  • Nicholas S. Dufault
  • Melinda R. Dornbusch
  • Deborah L. Allan
  • Carroll P. Vance
  • Deborah A. Samac
چکیده

Transgenic alfalfa over-expressing a nodule-enhanced malate dehydrogenase (neMDH) cDNA and untransformed alfalfa plants were grown at the same field site and rhizosphere soils collected after 53 weeks of plant growth. These alfalfa lines differ in the amount and composition of root organic acids produced and exuded into the rhizosphere. Nucleotide sequencing of PCR-based 16S ribosomal DNA (rDNA) clone libraries and Biologe GN microtiter plates were employed to assess the activity of naturally occurring rhizobacteria in the two alfalfa rhizospheres. Selected macroand micro-elements in the two alfalfa rhizosphere soils were also measured. Analysis of 240 16S rDNA clone sequences indicated the existence of about 11 bacterial phyla and their major subdivisions in the two alfalfa rhizosphere samples. There were qualitative changes in the abundance of bacterial phylogenetic groups between rhizosphere soils of transgenic and untransformed alfalfa. Carbon substrate utilization profiles suggested that rhizosphere samples from transgenic alfalfa had significantly greater microbial functional diversity compared with rhizosphere samples from untransformed alfalfa. The concentrations of nitric acid extractable P, K, Mn, Zn and Cu increased significantly in the transgenic alfalfa rhizosphere compared with the untransformed alfalfa rhizosphere. These observations indicate that organic acids produced by plant roots significantly influence rhizosphere microbial diversity and availability of macroand micro-nutrients and demonstrate the utility of such trangenic plants as tools for studying the potential impact of plant root exudates on soil microbial ecosystems. q 2003 Elsevier Science Ltd. All rights reserved.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Overexpression of malate dehydrogenase in transgenic alfalfa enhances organic acid synthesis and confers tolerance to aluminum.

Al toxicity is a severe impediment to production of many crops in acid soil. Toxicity can be reduced through lime application to raise soil pH, however this amendment does not remedy subsoil acidity, and liming may not always be practical or cost-effective. Addition of organic acids to plant nutrient solutions alleviates phytotoxic Al effects, presumably by chelating Al and rendering it less to...

متن کامل

An overview of plant growth promoting rhizobacteria and their influence on essential oils of medicinal plants: a review article.

One of the important and necessary practices for improving nutrients availability in sustainable agriculture is using microorganisms. Beside the negative effects of chemical fertilizers on the soil and human health, plant growth promoting rhizobacteria are known as an alternative to supply the organic nutrients of plants during the past two decades. Enriching soil fertility by eco-friendly meth...

متن کامل

Potential use of Iranian rhizobial strains as plant growth-promoting rhizobacteria (PGPR) and effects of selected strains on growth characteristics of wheat, corn and alfalfa

Abstract Many agricultural researches have been performed to improve soil productivity. Nitrogen (N) and Phosphorus (P) are essential elements which are utilized by the plants in large amounts. Phosphorus can be provided by applying chemical fertilizers. Microorganisms convert insoluble phosphate to the soluble form and some bacteria such as rhizobacteria play an important role in this proces...

متن کامل

پیامد مایه‌زنی خاک با ریزجانداران بردبار به فلزهای سنگین بر رشد گیاه و جذب سرب و کادمیم در سه گیاه مرتعی

Arbuscular mycorrhizae (AM) and Plant Growth Promoting Rhizobacteria (PGPR) associations are integral and functioning parts of plant roots. These associations have a basic role in root uptake efficiency as well as improvement of plant growth in degraded environments including heavy metals contaminated soils. This study was conducted to evaluate the effects of heavy metal-resistant soil microbe'...

متن کامل

Automatic classification of highly related Malate Dehydrogenase and L-Lactate Dehydrogenase based on 3D-pattern of active sites

Accurate protein function prediction is an important subject in bioinformatics, especially wheresequentially and structurally similar proteins have different functions. Malate dehydrogenaseand L-lactate dehydrogenase are two evolutionary related enzymes, which exist in a widevariety of organisms. These enzymes are sequentially and structurally similar and sharecommon active site residues, spati...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2003