Interplay between gasotransmitters and potassium is a K+ey factor during plant response to abiotic stress.

Carbon monoxide (CO), nitric oxide (NO) and hydrogen sulfide (H2S) are gasotransmitters known for their roles in plant response to (a)biotic stresses. The crosstalk between these gasotransmitters and potassium ions (K+) has received considerable attention in recent years, particularly due to the dual role of K+ as an essential mineral nutrient and a promoter of plant tolerance to abiotic stress. This review brings together what it is known about the interplay among NO, CO, H2S and K+ in plants with focus on the response to high salinity. Some findings obtained for plants under water deficit and metal stress are also presented and discussed since both abiotic stresses share similarities with salt stress. The molecular targets of the gasotransmitters NO, CO and H2S in root and guard cells that drive plant tolerance to salt stress are highlighted as well.

Chemical composition of cell wall changes during developmental stages of galls on Matayba guianensis (Sapindaceae): perspectives obtained by immunocytochemistry analysis.

The development of plant organs depends on cell division, elongation, structural and chemical changes, and reorganization of cell wall components. As phenotype manipulators, galling insects can manipulate the structure and metabolism of host tissues to build the gall. The gall formation depends on the rearrangement of cell wall components to allow cell growth and elongation, key step for the knowledge regarding gall development, and shape acquisition. Herein, we used an immunocytochemical approach to investigate the chemical composition of the cell wall during the development of galls induced by Bystracoccus mataybae (Eriococcidae) on leaflets of Matayba guianensis (Sapindaceae). Different developmental stages of non-galled leaflets (n = 10) and of leaflet galls (n = 10) were collected from the Cerrado (Brazilian savanna) for anatomical and immunocytochemical analysis. We found that the epitopes of (1 → 4) ß-D-galactans and (1 → 5) α-L-arabinans were evident in the tissues of the young and senescent galls. These epitopes seem to be associated with the mechanical stability maintenance and increased gall porosity. As well, the degree of methyl-esterification of pectins changed from the young to the senescent galls and revealed the conservation of juvenile cell and tissue features even in the senescent galls. The extensins detected in senescent galls seem to support their rigidity and structural reinforcement of these bodies. Our results showed a disruption in the pattern of deposition of leaflet cell wall for the construction of M. guianensis galls, with pectin and protein modulation associated with the change of the developmental gall stages.