Mono- and Digalactosyldiacylglycerol Lipids Function Nonredundantly to Regulate Systemic Acquired Resistance in Plants

Qing Ming Gao, Keshun Yu, Ye Xia, M. B. Shine, Caixia Wang, Du Roy Navarre, Aardra Kachroo, Pradeep Kachroo

Research output: Contribution to journalArticlepeer-review

73 Scopus citations

Abstract

The plant galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) have been linked to the anti-inflammatory and cancer benefits of a green leafy vegetable diet in humans due to their ability to regulate the levels of free radicals like nitric oxide (NO). Here, we show that DGDG contributes to plant NO as well as salicylic acid biosynthesis and is required for the induction of systemic acquired resistance (SAR). In contrast, MGDG regulates the biosynthesis of the SAR signals azelaic acid (AzA) and glycerol-3-phosphate (G3P) that function downstream of NO. Interestingly, DGDG is also required for AzA-induced SAR, but MGDG is not. Notably, transgenic expression of a bacterial glucosyltransferase is unable to restore SAR in dgd1 plants even though it does rescue their morphological and fatty acid phenotypes. These results suggest that MGDG and DGDG are required at distinct steps and function exclusively in their individual roles during the induction of SAR. The galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) constitute ~80% of total membrane lipids in plants. Gao etal. now show that these galactolipids function nonredundantly to regulate systemic acquired resistance (SAR). Furthermore, they show that the terminal galactose on the α-galactose-β-galactose head group of DGDG is critical for SAR.

Original languageEnglish
Pages (from-to)1681-1691
Number of pages11
JournalCell Reports
Volume9
Issue number5
DOIs
StatePublished - Dec 11 2014

Bibliographical note

Publisher Copyright:
© 2014 The Authors.

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology

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