The nitrogen fixing specie Sophora cassioides (Fabaceae), is nutritionally favored and their rhizosphere bacteria modified when is co-cultivated with the cluster root forming Embothrium coccineum (Proteaceae)

Abstract

The The hypothesis that Embothrium coccineum, a species able to solubilize P through cluster roots (CR) carboxylate exudation, makes P more available in volcanic depositions, thus facilitating the growth of other plant species such as the N-fixing Sophora cassioides was tested. In this work, seedlings of these two tree species were grown alone or co-cultivated for six months in greenhouse conditions with either pumice, a recent volcanic deposition with low P availability, or an organic commercial mix. Upon analyzing the aboveground growth of the two substrate treatments, we found no clear evidence of facilitation. Despite this, substrate type did influence the relative growth and some characteristics of CR and nodules. On the other side, the number of total soil bacteria, but not Rhizobium spp, was greater when E. coccineum and S. cassioidea were grown together than when only one species was grown alone. Nutritional parameters, such as the concentration of nitrogen (N) and phosphorous (P) in roots and total leaf protein content in leaves, indicated that the nutritional content of S. cassioides was greater when co-cultivated with E. coccineum in pumice. Specifically, co-cultivation tended to reduced P limitation and improved N acquisition by S. cassioides. Based on these results, our hypothesis is partially accepted.

In Situ Cultivation Approach to Increase the Culturable Bacterial Diversity in the Rhizobiome of Plants

“…A substantial number of studies have revealed that the rhizosphere of plants harbors thousands of different rhizobacterial taxa that can establish beneficial (e.g., plant growth-promoting bacteria), detrimental (e.g., phytopathogens), or symbiotic (e.g., N 2fixing bacteria) interactions with their host plants (Hinsinger et al 2005;Zúñiga-Feest et al 2018). Currently, most studies in the rhizosphere involve the isolation of culturable rhizobacteria, where in terms of taxonomic affiliation, they are commonly limited to four phyla taxa (Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria), which are recognized as the most abundant bacterial groups in soils (Lauber et al 2009).…”

The association between a nurse cushion plant and a cluster root‐bearing tree species alters the plant community structure

“…the reproductive output of Acaena decreased in the presence of Embothrium ). Similarly, in another study, the presence of Embothrium acted to increase the leaf protein content but reduce the relative growth rate of Sophora cassioides (Fabaceae) in a pumice substrate (Zúñiga‐Feest et al., ). Overall, our results provide empirical evidence of a negative feedback between a beneficiary species ( Embothrium ) and a benefactor species ( Acaena ) in line with findings from a global assessment where species in different environments were considered (Schöb, Callaway, et al., ).…”

“…Embothrium is a shade-intolerant species that colonizes highly disturbed areas where other tree species rarely occur, including areas with frequent volcanic ash deposition, lahars (layers of volcanic scoria subjected to high radiation and low night temperatures), glacial moraines, and along roadsides (Alberdi & Donoso, 2004;Veblen & Ashton, 1978). Previous studies have reported an increase in the formation of cluster roots in Embothrium in response to low levels of soil P and N availability (Piper et al, 2013;Zúñiga-Feest, Delgado, & Alberdi, 2010;Zúñiga-Feest et al, 2018).…”

“…Embothrium exudes nine times more carboxylates per unit cluster root weight than its counterparts from south-western Australia, which has been hypothesized as an adaptation to volcanic soils, rich in total P but low in available P (Delgado, Suriyagoda, Zúñiga-Feest, Borie, & Lambers, 2014). Accordingly, seedlings of Embothrium exhibit a significantly higher cluster root formation and carboxylate exudation in young volcanic substrates than in more developed soils (Ávila-Valdés, Piper, & Zúñiga-Feest, 2019;Piper et al, 2013;Zúñiga-Feest et al, 2018). Knowing that cushion plants (e.g.…”

Linking rhizosphere bacterial diversity and soil fertility in tobacco plants under different soil types and cropping pattern in Tanzania: A pilot study

“…Since tobacco is a dense nutrients feeder crop, more uptakes of P, K and S result in decreasing levels of these nutrients in the soil ( Table 1 ). On the other hand, bacteria species under Proteobacteria have also been reported to fix N in the soils and hence increasing soil total N after tobacco ( Table 1 ; Balsanelli et al., 2015 ; Trovero et al., 2018 ; Zúñiga-Feest et al., 2018 ). Chloroflexi, another dominant phylum identified in tobacco growing areas, reported to catalase Mn and also involved in the nitrification process in soils ( Sorokin et al., 2012 ; Baginski and Sommerhalter, 2017 ).…”