Exploring ComQXPA quorum-sensing diversity and biocontrol potential of Bacillus spp. isolates from tomato rhizoplane.

Bacillus subtilis is a widespread and diverse bacterium t exhibits a remarkable intraspecific diversity of the ComQXPA quorum-sensing (QS) system. This manifests in the existence of distinct communication groups (pherotypes) that can efficiently communicate within a group, but not between groups. Similar QS diversity was also found in other bacterial species, and its ecological and evolutionary meaning is still being explored.

The Papaver self-incompatibility pollen S-determinant, PrpS, functions in Arabidopsis thaliana.

Many angiosperms use specific interactions between pollen and pistil proteins as "self" recognition and/or rejection mechanisms to prevent self-fertilization. Self-incompatibility (SI) is encoded by a multiallelic S locus, comprising pollen and pistil S-determinants. In Papaver rhoeas, cognate pistil and pollen S-determinants, PrpS, a pollen-expressed transmembrane protein, and PrsS, a pistil-expressed secreted protein, interact to trigger a Ca(2+)-dependent signaling network, resulting in inhibition of pollen tube growth, cytoskeletal alterations, and programmed cell death (PCD) in incompatible pollen.

The pollen S-determinant in Papaver: comparisons with known plant receptors and protein ligand partners.

Cell-cell communication is vital to multicellular organisms and much of it is controlled by the interactions of secreted protein ligands (or other molecules) with cell surface receptors. In plants, receptor-ligand interactions are known to control phenomena as diverse as floral abscission, shoot apical meristem maintenance, wound response, and self-incompatibility (SI). SI, in which 'self' (incompatible) pollen is rejected, is a classic cell-cell recognition system.

Initiation of programmed cell death in self-incompatibility: role for cytoskeleton modifications and several caspase-like activities.

Programmed cell death (PCD) is an important and universal process regulating precise death of unwanted cells in eukaryotes. In plants, the existence of PCD has been firmly established for about a decade, and many components shown to be involved in apoptosis/PCD in mammalian systems are found in plant cells undergoing PCD. Here, we review work from our lab demonstrating the involvement of PCD in the self-incompatibility response in Papaver rhoeas pollen.

Identification of the pollen self-incompatibility determinant in Papaver rhoeas.

Higher plants produce seed through pollination, using specific interactions between pollen and pistil. Self-incompatibility is an important mechanism used in many species to prevent inbreeding; it is controlled by a multi-allelic S locus. 'Self' (incompatible) pollen is discriminated from 'non-self' (compatible) pollen by interaction of pollen and pistil S locus components, and is subsequently inhibited.

Microtubules are a target for self-incompatibility signaling in Papaver pollen.

Perception and integration of signals into responses is of crucial importance to cells. Both the actin and microtubule cytoskeleton are known to play a role in mediating diverse stimulus responses. Self-incompatibility (SI) is an important mechanism to prevent self-fertilization.