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

Ziv Attia, Ahan Dalal, Menachem Moshelion*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Plants can detect pathogen invasion by sensing microbe-associated molecular patterns (MAMPs). This sensing process leads to the induction of defense responses. Numerous MAMP mechanisms of action have been described in and outside the guard cells. Here, we describe the effects of chitin, a MAMP found in fungal cell walls and insects, on the cellular osmotic water permeability (Pf) of the leaf vascular bundle-sheath (BS) and mesophyll cells (MCs), and its subsequent effect on leaf hydraulic conductance (Kleaf). BS is a parenchymatic tissue that tightly encases the vascular system. BS cells (BSCs) have been shown to influence Kleaf through changes in their Pf, for example, after sensing the abiotic stress response-regulating hormone abscisic acid. It was recently reported that, in Arabidopsis, the chitin receptors-like kinases, 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 BSCs and MCs exhibit a sharp decrease in Pf in response to chitin treatment. In addition, xylem-fed chitin decreased Kleaf and led to stomatal closure. However, Atlyk5 mutant showed none of these responses. Complementing AtLYK5 in the BSCs (using the SCARECROW promoter) resulted in the response to chitin that was similar to that observed in the wild-type. These results suggest that BS play a role in the perception of apoplastic chitin and in initiating chitin-triggered immunity.

Original languageAmerican English
Pages (from-to)1368-1377
Number of pages10
JournalPlant Journal
Issue number6
StatePublished - 1 Mar 2020

Bibliographical note

Funding Information:
This research was supported by the Israel Ministry of Agriculture and Rural Development (Eugene Kandel Knowledge Centers) as part of the Root of the Matter – The Root‐Zone Knowledge Center for Leveraging Modern Agriculture and by the Israel Science Foundation (ISF Grant No. 878/16). A.D. gratefully acknowledges the Planning and Budgeting Committee (PBC) of the Council for Higher Education (CHE), Israel, for his postdoctoral fellowship. The authors thank Dr Ofir Bahar for his scientific advice and critical reading of this paper.

Publisher Copyright:
© 2019 The Authors The Plant Journal © 2019 John Wiley & Sons Ltd


  • bundle-sheath cell
  • chitin
  • leaf hydraulic conductance
  • microbe-associated molecular pattern
  • osmotic water permeability
  • pattern-triggered immunity


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