Signaling in the phytomicrobiome: breadth and potential

Abstract

Higher plants have evolved intimate, complex, subtle, and relatively constant relationships with a suite of microbes, the phytomicrobiome. Over the last few decades we have learned that plants and microbes can use molecular signals to communicate. This is well-established for the legume-rhizobia nitrogen-fixing symbiosis, and reasonably elucidated for mycorrhizal associations. Bacteria within the phytomircobiome communicate among themselves through quorum sensing and other mechanisms. Plants also detect materials produced by potential pathogens and activate pathogen-response systems. This intercommunication dictates aspects of plant development, architecture, and productivity. Understanding this signaling via biochemical, genomics, proteomics, and metabolomic studies has added valuable knowledge regarding development of effective, low-cost, eco-friendly crop inputs that reduce fossil fuel intense inputs. This knowledge underpins phytomicrobiome engineering: manipulating the beneficial consortia that manufacture signals/products that improve the ability of the plant-phytomicrobiome community to deal with various soil and climatic conditions, leading to enhanced overall crop plant productivity.

The diversity of soil microbial communities matters when legumes face drought

“…Altogether, this suggests that the high microbial diversity could have stimulated lateral root branching, thus enhancing root prospection in the soil and water perception by roots and leading to a higher stomatal conductance (see review by Blessing, Mariette, Kaloli, & Bramley, 2018). Some soil microbial species, known as plant growth promoting bacteria, secrete compounds able to modify root architecture (Mabood, Zhou, & Smith, 2014;Prudent, Salon, Souleimanov, Emery, & Smith, 2015;Smith, Subramanian, Lamont, & Bywater-Ekegärd, 2015) and lead to higher water and N uptake. In this study, although no evidence of microbial diversity impact was observed on the growth of 5-week-old wellwatered plants, the decrease in microbial diversity had important negative consequences on pea productivity, as revealed by the lower grain biomass produced by the plants.…”

Advances in Eco-Efficient Agriculture: The Plant-Soil Mycobiome

“…Moreover, better appreciation of the phytomicrobiome [64,65] will help in increasing the understanding of crop cycles [66]. Knowing the mycotrophic status of plant species is an important piece of information for plant cultivation, ecological restoration, and for screening for plant stress tolerance.…”

“…Integrated crop-livestock systems can promote synergy between agricultural production and environmental quality mimicking the reality and diversity of natural rural systems [51,53]. In this context, the mycorrhizal fungi are crucial contributors of the phytomicrobiome (the complex plant associations with microbial communities [76]), and interactions with plant roots are also of importance in the rhizomicrobiome [64,66,77].…”

Introducing Natural Farming in Black Pepper (Piper nigrumL.) Cultivation

“…Smith et al [13] opined that the foundation of Natural Farming production lies in the health of the soil. A fertile soil provides essential nutrients to the growing crop and helps support a diverse and active biotic community.…”

“…The important consideration here is the careful selection of a mixed culture of compatible, effective microorganisms properly cultured and provided with acceptable organic substrates [12,13]. In Natural Farming, these beneficial microorganisms can be grown to high populations and then applied to soils that also have a large stable population of beneficial microorganisms, especially facultative anaerobic bacteria [14].…”