Deficiencies in cluster-2 ALA lipid flippases result in salicylic acid-dependent growth reductions
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Deficiencies in cluster-2 ALA lipid flippases result in salicylic acid-dependent growth reductions. / Davis, James A.; Poulsen, Lisbeth R.; Kjeldgaard, Bodil; Moog, Max W.; Brown, Elizabeth; Palmgren, Michael; López-Marqués, Rosa L.; Harper, Jeffrey F.
In: Physiologia Plantarum, Vol. 176, No. 2, e14228, 2024.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Deficiencies in cluster-2 ALA lipid flippases result in salicylic acid-dependent growth reductions
AU - Davis, James A.
AU - Poulsen, Lisbeth R.
AU - Kjeldgaard, Bodil
AU - Moog, Max W.
AU - Brown, Elizabeth
AU - Palmgren, Michael
AU - López-Marqués, Rosa L.
AU - Harper, Jeffrey F.
N1 - Publisher Copyright: © 2024 Scandinavian Plant Physiology Society.
PY - 2024
Y1 - 2024
N2 - P4 ATPases (i.e., lipid flippases) are eukaryotic enzymes that transport lipids across membrane bilayers. In plants, P4 ATPases are named Aminophospholipid ATPases (ALAs) and are organized into five phylogenetic clusters. Here we generated an Arabidopsis mutant lacking all five cluster-2 ALAs (ala8/9/10/11/12), which is the most highly expressed ALA subgroup in vegetative tissues. Plants harboring the quintuple knockout (KO) show rosettes that are 2.2-fold smaller and display chlorotic lesions. A similar but less severe phenotype was observed in an ala10/11 double KO. The growth and lesion phenotypes of ala8/9/10/11/12 mutants were reversed by expressing a NahG transgene, which encodes an enzyme that degrades salicylic acid (SA). A role for SA in promoting the lesion phenotype was further supported by quantitative PCR assays showing increased mRNA abundance for an SA-biosynthesis gene ISOCHORISMATE SYNTHASE 1 (ICS1) and two SA-responsive genes PATHOGENESIS-RELATED GENE 1 (PR1) and PR2. Lesion phenotypes were also reversed by growing plants in liquid media containing either low calcium (~0.1 mM) or high nitrogen concentrations (~24 mM), which are conditions known to suppress SA-dependent autoimmunity. Yeast-based fluorescent lipid uptake assays revealed that ALA10 and ALA11 display overlapping substrate specificities, including the transport of LysoPC signaling lipids. Together, these results establish that the biochemical functions of ALA8–12 are at least partially overlapping, and that deficiencies in cluster-2 ALAs result in an SA-dependent autoimmunity phenotype that has not been observed for flippase mutants with deficiencies in other ALA clusters.
AB - P4 ATPases (i.e., lipid flippases) are eukaryotic enzymes that transport lipids across membrane bilayers. In plants, P4 ATPases are named Aminophospholipid ATPases (ALAs) and are organized into five phylogenetic clusters. Here we generated an Arabidopsis mutant lacking all five cluster-2 ALAs (ala8/9/10/11/12), which is the most highly expressed ALA subgroup in vegetative tissues. Plants harboring the quintuple knockout (KO) show rosettes that are 2.2-fold smaller and display chlorotic lesions. A similar but less severe phenotype was observed in an ala10/11 double KO. The growth and lesion phenotypes of ala8/9/10/11/12 mutants were reversed by expressing a NahG transgene, which encodes an enzyme that degrades salicylic acid (SA). A role for SA in promoting the lesion phenotype was further supported by quantitative PCR assays showing increased mRNA abundance for an SA-biosynthesis gene ISOCHORISMATE SYNTHASE 1 (ICS1) and two SA-responsive genes PATHOGENESIS-RELATED GENE 1 (PR1) and PR2. Lesion phenotypes were also reversed by growing plants in liquid media containing either low calcium (~0.1 mM) or high nitrogen concentrations (~24 mM), which are conditions known to suppress SA-dependent autoimmunity. Yeast-based fluorescent lipid uptake assays revealed that ALA10 and ALA11 display overlapping substrate specificities, including the transport of LysoPC signaling lipids. Together, these results establish that the biochemical functions of ALA8–12 are at least partially overlapping, and that deficiencies in cluster-2 ALAs result in an SA-dependent autoimmunity phenotype that has not been observed for flippase mutants with deficiencies in other ALA clusters.
U2 - 10.1111/ppl.14228
DO - 10.1111/ppl.14228
M3 - Journal article
C2 - 38413387
AN - SCOPUS:85186402216
VL - 176
JO - Physiologia Plantarum
JF - Physiologia Plantarum
SN - 0031-9317
IS - 2
M1 - e14228
ER -
ID: 385228574