scholarly journals Vascular bundle sheath and mesophyll cells modulate leaf water balance in response to chitin

2019 ◽  
Vol 101 (6) ◽  
pp. 1368-1377 ◽  
Author(s):  
Ziv Attia ◽  
Ahan Dalal ◽  
Menachem Moshelion
Keyword(s):  
Water Balance ◽  
Vascular Bundle ◽  
Bundle Sheath ◽  
Leaf Water ◽  
Mesophyll Cells ◽  
Leaf Water Balance

scholarly journals Vascular bundle sheath and mesophyll regulation of leaf water balance in response to chitin

2018 ◽  
Author(s):  
Ziv Attia ◽  
Ahan Dalal ◽  
Menachem Moshelion
Keyword(s):  
Water Balance ◽  
Vascular Bundle ◽  
Vascular System ◽  
Defense Responses ◽  
Hydraulic Conductance ◽  
Bundle Sheath ◽  
Leaf Water ◽  
Receptor Kinase ◽  
Mesophyll Cells ◽  
Leaf Water Balance

ABSTRACTPlants can detect pathogen invasion by sensing pathogen-associated molecular patterns (PAMPs). This sensing process leads to the induction of defense responses. Most PAMP mechanisms of action have been described in the guard cells. Here, we describe the effects of chitin, a PAMP found in fungal cell walls, on the cellular osmotic water permeability (Pf) of the leaf vascular bundle-sheath (BS) and mesophyll cells and its subsequent effect on leaf hydraulic conductance (Kleaf).The BS is a parenchymatic tissue that tightly encases the vascular system. BS cells have been shown to controlKleafthrough changes in theirPf, for example, in response to ABA. It was recently reported that, in Arabidopsis, the chitin receptors chitin elicitor receptor kinase 1 (CERK1) and LYSINE MOTIF RECEPTOR KINASE 5 (LYK5) are highly expressed in the BS, as well as the neighboring mesophyll. Therefore, we studied the possible impact of chitin on these cells.Our results revealed that both BS cells and mesophyll cells exhibit a sharp decrease inPfin response to chitin treatment. In addition, xylem-fed chitin decreasedKleafand led to stomatal closure. However, anAtlyk5mutant showed none of these responses. ComplimentingAtLYK5specifically in the BS cells (using the SCARECROW promoter) and transient expresion in mesophyll cells each resulted in a response to chitin that was similar to that observed in the wild type. These results suggest that BS and mesophyll cells each play a role in the perception of apoplastic chitin and in initiating chitin-triggered immunity.Significance StatementPAMP perception by plant receptors triggers various defense responses important for plant immunity. Here we provide new insights into a topic that has received a great deal of previous attention, revealing that a chitin immune response is present in additional leaf tissues other than the stomata. Chitin perception by the bundle sheath cells enwrapping the whole leaf vascular system decrease its cellular osmotic permeability and leaf hydraulic conductance. This in turn, leads to hydraulic signals being sent to the stomata and regulates whole-leaf water balance in response to chitin application and, perhaps, during fungal infection. Emphasizing the dynamic role of the BS in chitin-sensing and water balance regulation.

scholarly journals Arabidopsis leaf hydraulic conductance is regulated by xylem-sap pH, controlled, in turn, by a P-type H+-ATPase of vascular bundle sheath cells

2017 ◽  
Author(s):  
Yael Grunwald ◽  
Noa Wigoda ◽  
Nir Sade ◽  
Adi Yaaran ◽  
Tanmayee Torne ◽  
...  
Keyword(s):  
Proton Pump ◽  
Vascular Bundle ◽  
Xylem Sap ◽  
Hydraulic Conductance ◽  
Bundle Sheath ◽  
List Type ◽  
Mesophyll Cells ◽  
Leaf Hydraulic Conductance ◽  
Bundle Sheath Cells ◽  
Sheath Cells

AbstractThe leaf vascular bundle sheath cells (BSCs) that tightly envelop the leaf veins, are a selective and dynamic barrier to xylem-sap water and solutes radially entering the mesophyll cells. Under normal conditions, xylem-sap pH of <6 is presumably important for driving and regulating the transmembranal solute transport. Having discovered recently a differentially high expression of a BSCs proton pump, AHA2, we now test the hypothesis that it regulates this pH and leaf radial water fluxes.We monitored the xylem-sap pH in the veins of detached leaves of WT Arabidopsis, AHA mutants, and aha2 mutants complemented with AHA2 gene solely in BSCs. We tested an AHA inhibitor and stimulator, and different pH buffers. We monitored their impact on the xylem-sap pH and the whole leaf hydraulic conductance (Kleaf), and the effect of pH on the water osmotic permeability (Pf) of isolated BSCs protoplasts.Our results demonstrated that AHA2 is necessary for xylem-sap acidification, and in turn, for elevating Kleaf. Conversely, knocking out AHA2 alkalinized the xylem-sap. Also, elevating xylem sap pH to 7.5 reduced Kleaf and elevating external pH to 7.5 decreased the BSCs Pf.All these demonstrate a causative link between AHA2 activity in BSCs and leaf radial water conductance.One-sentence summaryBundle-sheath cells can control the leaf hydraulic conductance by proton-pump-regulated xylem sap pH

scholarly journals Leaf Water Balance During Oscillation of Stomatal Aperture

1969 ◽  
Vol 44 (6) ◽  
pp. 826-830 ◽  
Author(s):  
A. R. G. Lang ◽  
Betty Klepper ◽  
Malcolm J. Cumming
Keyword(s):  
Water Balance ◽  
Leaf Water ◽  
Stomatal Aperture ◽  
Leaf Water Balance

Leaf ultrastructure in species of Gomphrena and Pfaffia (Amaranthaceae)

1984 ◽  
Vol 62 (4) ◽  
pp. 812-817 ◽  
Author(s):  
Maria Emília Estelita-Teixeira ◽  
Walter Handro
Keyword(s):  
Vascular Bundle ◽  
Bundle Sheath ◽  
Chloroplast Structure ◽  
Leaf Ultrastructure ◽  
Mesophyll Cells ◽  
Lamellar System ◽  
Kranz Anatomy ◽  
Companion Cells ◽  
Bundle Sheath Cells ◽  
Vascular Parenchyma

Ultrastructural aspects, especially the organization of chloroplasts and their distribution, were studied in leaves of three species of Gomphrena (G. macrocephala, G. prostrata, and G. decipiens) presenting "Kranz anatomy," and in Pfaffia jubata, without that characteristic. In Gomphrena spp. the distribution of chloroplasts according to the complexity of their lamellar system seems to follow a gradient: most of the chloroplasts in the bundle sheath cells have poorly developed grana but some of them, in the cell side opposite to the vascular bundle, may present conspicuous grana. A similar situation occurs in "Kranz mesophyll cells," but in this case grana are more developed. Finally, chloroplasts in "non-Kranz mesophyll cells" have the more developed grana. In P. jubata no differences occur in chloroplast structure, all of them showing well-organized grana. Chloroplasts with well-developed grana were found in vascular parenchyma and in companion cells of Gomphrena spp. and P. jubata.

Correlated evolution in traits influencing leaf water balance in Dendrobium (Orchidaceae)

Plant Ecology ◽  
2014 ◽  
Vol 215 (11) ◽  
pp. 1255-1267 ◽  
Author(s):  
Mei Sun ◽  
Shi-Jian Yang ◽  
Jiao-Lin Zhang ◽  
Megan Bartlett ◽  
Shi-Bao Zhang
Keyword(s):  
Water Balance ◽  
Leaf Water ◽  
Correlated Evolution ◽  
Leaf Water Balance

scholarly journals The maize Aliphatic Suberin Feruloyl Transferase genes affect leaf water movement but are dispensable for bundle sheath CO2 concentration

2020 ◽  
Author(s):  
Rachel A. Mertz ◽  
Patrick Ellsworth ◽  
Patricia Ellsworth ◽  
S. Lori Tausta ◽  
Susanne von Caemmerer ◽  
...  
Keyword(s):  
Cell Wall ◽  
Carbon Fixation ◽  
Water Movement ◽  
Bundle Sheath ◽  
Leaf Water ◽  
Loss Of Function ◽  
Wild Type ◽  
Ambient Conditions ◽  
Mesophyll Cells ◽  
Suberin Lamellae

ABSTRACTC4 grasses often outperform C3 species under hot, arid conditions due to superior water and nitrogen use efficiencies and lower rates of photorespiration. A method of concentrating CO2 around the site of carbon fixation in the bundle sheath (BS) is required to realize these gains. In NADP-malic enzyme (NADP-ME)-type C4 grasses such as maize, suberin deposition in the BS cell wall is hypothesized to act as a diffusion barrier to CO2 escape and O2 entry from surrounding mesophyll cells. Suberin is a heteropolyester comprised of acyl-lipid-derived aliphatic and phenylpropanoid-derived aromatic components. To disrupt BS suberization, we mutated two paralogously duplicated, unlinked maize orthologues of Arabidopsis thaliana ALIPHATIC SUBERIN FERULOYL TRANSFERASE, ZmAsft1 and ZmAsft2, using closely linked Dissociation transposons. Loss-of-function double mutants revealed a 97% reduction in suberin-specific omega-hydroxy fatty acids without a stoichiometric decrease in ferulic acid. However, BS suberin lamellae were deficient in electron opaque material, and cohesion between the suberin lamellae and polysaccharide cell walls was attenuated in double mutants. There were no other morphological phenotypes under ambient conditions. Furthermore, there was no significant effect on net CO2 assimilation at any intercellular CO2 concentration, and no effect on 13C isotope discrimination relative to wild type. Thus, ZmAsft expression is not required to establish a functional CO2 concentrating mechanism in in maize. Double mutant leaves exhibit elevated cell wall elasticity, transpirational, and stomatal conductance relative to WT. Thus, the ZmAsft genes are dispensable for gas exchange barrier function but may be involved in regulation of leaf water movement.One-sentence SummaryDouble mutants of two paralogously duplicated maize Aliphatic Suberin Feruloyl Transferase (ZmAsft) genes exhibit reduced aliphatic suberin content, cell wall cohesion defects, and elevated leaf transpiration, but no changes in CO2 assimilation relative to wild type.

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