Perenniality, more than genotypes, shapes biological and chemical rhizosphere composition of perennial wheat lines

Abstract

Perennial grains provide various ecosystem services compared to the annual counterparts thanks to their extensive root system and permanent soil cover. However, little is known about the evolution and diversification of perennial grains rhizosphere and its ecological functions over time. In this study, a suite of -OMICSs - metagenomics, enzymomics, metabolomics and lipidomics - was used to compare the rhizosphere environment of four perennial wheat lines at the first and fourth year of growth in comparison with an annual durum wheat cultivar and the parental species Thinopyrum intermedium. We hypothesized that wheat perenniality has a greater role in shaping the rhizobiome composition, biomass, diversity, and activity than plant genotypes because perenniality affects the quality and quantity of C input – mainly root exudates – hence modulating the plant-microbes crosstalk. In support of this hypothesis, the continuous supply of sugars in the rhizosphere along the years created a favorable environment for microbial growth which is reflected in a higher microbial biomass and enzymatic activity. Moreover, modification in the rhizosphere metabolome and lipidome over the years led to changes in the microbial community composition favoring the coexistence of more diverse microbial taxa, increasing plant tolerance to biotic and abiotic stresses. Despite the dominance of the perenniality effect, our data underlined that the OK72 line rhizobiome distinguished from the others by the increase in abundance of Pseudomonas spp., most of which are known as potential beneficial microorganisms, identifying this line as a suitable candidate for the study and selection of new perennial wheat lines.

Positive Effects of Perennial Wheat on Soil Fertility, Carbon Stocks and Microbial Biomass in South-Eastern Kazakhstan

“…Microbial biomass is an important living component of soil; it also plays a major role in the formation of soil aggregates [34][35][36][37]. In the conditions of sub-humid Mediterranean climate, a comparison of the rhizosphere environment of perennial wheat at the first and fourth year of growth revealed an increase in microbial biomass and enzymatic activity, and an increase in the diversity of microbial community composition [38,39].…”

Alfalfa Plant Age (3 to 8 Years) Affects Soil Physicochemical Properties and Rhizosphere Microbial Communities in Saline–Alkaline Soil

“…Consequently, this imbalance disrupts the microbial community structure and causes ecological degradation of the soil [20]. In general, the root exudates of perennial plants affect the quantity, structure, and function of soil microorganisms [21]. With increasing years of cultivation, both plant yield and rhizosphere microbial diversity significantly decrease [22].…”