Meristematic Connectome: A Cellular Coordinator of Plant Responses to Environmental Signals?

Abstract

Mechanical stress in tree roots induces the production of reaction wood (RW) and the formation of new branch roots, both functioning to avoid anchorage failure and limb damage. The vascular cambium (VC) is the factor responsible for the onset of these responses as shown by their occurrence when all primary tissues and the root tips are removed. The data presented confirm that the VC is able to evaluate both the direction and magnitude of the mechanical forces experienced before coordinating the most fitting responses along the root axis whenever and wherever these are necessary. The coordination of these responses requires intense crosstalk between meristematic cells of the VC which may be very distant from the place where the mechanical stress is first detected. Signaling could be facilitated through plasmodesmata between meristematic cells. The mechanism of RW production also seems to be well conserved in the stem and this fact suggests that the VC could behave as a single structure spread along the plant body axis as a means to control the relationship between the plant and its environment. The observation that there are numerous morphological and functional similarities between different meristems and that some important regulatory mechanisms of meristem activity, such as homeostasis, are common to several meristems, supports the hypothesis that not only the VC but all apical, primary and secondary meristems present in the plant body behave as a single interconnected structure. We propose to name this structure “meristematic connectome” given the possibility that the sequence of meristems from root apex to shoot apex could represent a pluricellular network that facilitates long-distance signaling in the plant body. The possibility that the “meristematic connectome” could act as a single structure active in adjusting the plant body to its surrounding environment throughout the life of a plant is now proposed.

Key Pathways and Genes of Arabidopsis thaliana and Arabidopsis halleri Roots under Cadmium Stress Responses: Differences and Similarities

“…During the past decades, hundreds of hyperaccumulator plants have been identified and a wide variety of in-wet experiments have been attempted to achieve a careful description of the biology underlying this trait [45,46]. Despite this, the hyperaccumulation trait still needs to be dissected and, in this sense, bioinformatics may provide tools for the comprehensive analysis and modeling of the related processes, as already applied for various purposes in plant biology studies [4,[47][48][49][50].…”

Network-Based Analysis to Identify Hub Genes Involved in Spatial Root Response to Mechanical Constrains

“…The connection of these distal portions could require short-distance chemical and electrical signalling [62,63] and hydraulic pulse, along with the plasma membrane network [64] and plasmodesmata over a longer distance. It could also involve the "meristematic connectome", a recently hypothesized physical cellular network for rapid communication through the plant body's distant compartments [65].…”

The adaptability of Ulmus pumila and the sensitivity of Populus sibirica to semi-arid steppe is reflected in the stem and root vascular cambium and anatomical wood traits

“…However, the current body of knowledge does not provide information on the impact of the environmental conditions and management practices on the cambial tissue and wood anatomical traits. The plant secondary growth is orchestrated by the cambium, longitudinal tissue present in both the above and belowground organs (Chiatante et al, 2021), whose complexity regarding its form and function has contributed to various definition attempts. In the present study, we rely on the definition proposed by the International Association of Wood Anatomists (IAWA, 1964) for the vascular cambium (VC) as 'the actively dividing layer of cells that lies between, and gives rise to, secondary xylem and phloem'.…”