Kin recognition is a nutrient-dependent inducible phenomenon

Abstract

Recognition and response to prospective competitors are crucial variables that must be considered in resource distribution and utilization in plant communities. Associated behaviors are largely mediated through the exchange of low-molecular weight exudates. These cues can significantly alter the root system architecture (RSA) between neighboring plants and are routinely sensitive enough to distinguish between plants of the same or different accessions, a phenomenon known as kin recognition (KR). Such refined discrimination of identity, based on the composition and detection of patterns of exudate signals is remarkable and provides insight into the chemical ecology of plant-plant interactions. The discovery that KR occurs in Arabidopsis thaliana provides a model system to resolve many of the mechanistic questions associated with this process. We hypothesized that the low-molecular weight cues which direct changes to the RSA during KR was driven by nutrient availability. Here we present evidence in support of a nutrient-inducible model for KR. Our findings underscore how exudate production and detection are influenced by nutrient availability as well as how this information is integrated into 'decisions' about competition and root system architecture which may have broader impacts on community composition.

Kin recognition in rice (Oryza sativa) lines

“…The impact of root competition on root placement patterns and behavioral responses is well known (Bartelheimer et al ., ; Semchenko et al ., ; Schmid et al ., ). Recent studies have shown that root exudates may alter root architecture during kin recognition in plants (Semchenko et al ., ; Palmer et al ., ). This study indicated that the focal rice cultivars could optimize their root systems in response to kin or nonkin.…”

“…These signals trigger complex plant response strategies, such as shade avoidance, alteration of biomass allocation patterns, and biochemical behaviors (Bais, ; Crepy & Casal, ). Although chemical‐mediated kin recognition responses may take place through aboveground volatiles, most evidence suggests root exudates as the signal of relatedness (Biedrzycki et al ., , ; Semchenko et al ., ; Palmer et al ., ). In this study, kin recognition responses still occurred with nylon mesh that segregated root systems, indicating that kin recognition in rice lines is driven by root‐secreted chemicals or microbial interactions rather than direct root contact.…”

The analysis of plant root responses to nutrient concentration, soil volume and neighbour presence: Different statistical approaches reflect different underlying basic questions

“…The collection of root exudates, in the forms of solutions (Biedrzycki et al., 2010) or leachates (Semchenko et al., 2014), from themselves and neighbours may differ from each other not only in the identity cues but also in nutrient composition. Thus, the nutrient contents, nitrogen and phosphorus in particular (Palmer et al., 2016), in the collections should be adjusted to a similar level before exposing focal plants to these collections.…”

Redox-mediated quorum sensing in plants

“…Beyond their role in regulating plant-microbial associations, insights into the plant’s contribution to this signaling landscape has emerged from studies on: (i) host recognition by parasitic plants [ 9 – 12 ], (ii) kin recognition/selection [ 13 – 16 ], and (iii) allelopathy [ 17 , 18 ]. Our understanding of the redox dynamics of these chemical networks has expanded significantly with the discovery of semagenesis [ 19 , 20 ].…”