Alleviation of Salt Stress in Legumes by Co-inoculation with Pseudomonas and Rhizobium

Abstract

Numerous studies have shown that soil salinity decreases nodulation and dramatically reduces N 2 fi xation and nitrogenase activity of nodulated legumes. Thus, the development of salt-tolerant symbioses is an absolute necessity to enable cultivation of leguminous crops in salt-affected soils. Dual inoculation of legumes with plant growth-promoting rhizobacteria (PGPR) and rhizobia has been reported to increase the number of nodules compared to those formed by a rhizobial strain alone. The production of IAA by Pseudomonas strains represents a benefi cial mechanism that promoted enlargement of root system and thereby further enhanced nutrient uptake, nodulation, and shoot growth of leguminous plants. When PGPR are able to alleviate salt stress experienced by the plant, more nodules might develop into nitrogen-fi xing ones, thereby enabling the plant to obtain part of its nitrogen from the atmosphere. Co-inoculation techniques could be a new approach to increase

COMBINED APPLICATION OF ARBUSCULAR MYCORRHIZAE FUNGI AND PLANT GROWTH PROMOTING BACTERIA IMPROVES GROWTH AND NUTRIENT UPTAKE EFFICIENCY OF PEA (Pisum sativum L.) PLANTS

“…Indeed, as it was previously reported, the salt stress can affect the AM fungi by slowing down the root colonization, spore germination and hyphal growth [Jahromi et al 2008, Abeer et al 2015. Meanwhile, salinity leads to a failure in the establishment of rhizobia, either by reducing the survival rate and proliferation of rhizobia in the soil and rhizosphere, or by inhibiting the root hair colonization [Egamberdieva et al 2013].…”

“…Indeed, the growth promoting effects of bacteria were stronger than AM fungi and differences with either AMF+ or Ctr plants were statistically significant in both non-saline and saline (20 and 50 mM NaCl) conditions. As a matter of fact, ameliorative effects of bacteria on plant growth under saline conditions have been reported for various plant species (tomato, pepper, canola, bean, and lettuce) [Egamberdieva et al 2013]. The stimulation of plant growth by PGPB might be a consequence of synthesis of phytohormones (such as auxins, cytokinins, and gibberellins) that promote shoots and entire plant growth Glick 2014, Bona et al 2015].…”

“…Like most of legumes, pea is very sensitive to salinity [Egamberdieva et al 2013]. Severe growth retardation [Meça et al 2016[Meça et al , 2017 and yield and protein reduction effects due to increased salinity are largely reported.…”

“…Whereas, it is largely known that legume crops have the ability to establish symbiosis with bacteria, collectively known as rhizobia, which induce root nodules where biological nitrogen fixation takes place [Peix et al 2014]. In addition, other PGPR species like Burkholderia, are able to increase root and shoot growth and the total biomass of plants [Egamberdieva et al 2013].…”

Could the artificial inoculation of AM fungi improve the benefits of using pea (Pisum sativum L.) plants for soil amendment purposes in greenhouses?

“…Under these circumstances, the use of commercial inoculants containing arbuscular a E-mail: aballiu@ubt.edu.al mycorrhizal fungi (AMF) is quickly expanding, rewarded as an environmentally friendly technology which contributes to the alleviation ofthe negative effects of soil/irrigation water salinity. Considering that most legumes are rather sensitive to salinity, and only a few legumes can grow in salt-affected soils (Egamberdieva et al, 2013), the objective of this study was to assess the impact of AMF inoculants containing a mixture of AM fungi (Glomus intraradices, Glomus etunicatum, Glomus mosseae, Glomus geosporum, and Glomus clarum) on plant growth parameters and nutrient absorption capacity of garden pea (Pisum sativum L.) grown as green manure crop in organic greenhouses, under normal and saline conditions.…”