Characterization of potato (Solanum tuberosum) and tomato (Solanum lycopersicum) protein phosphatases type 2A catalytic subunits and their involvement in stress responses

Abstract

Protein phosphorylation/dephosphorylation plays critical roles in stress responses in plants. This report presents a comparative characterization of the serine/threonine PP2A catalytic subunit family in Solanum tuberosum (potato) and S. lycopersicum (tomato), two important food crops of the Solanaceae family, based on the sequence analysis and expression profiles in response to environmental stress. Sequence homology analysis revealed six isoforms in potato and five in tomato clustered into two subfamilies (I and II). The data presented in this work show that the expression of different PP2Ac genes is regulated in response to environmental stresses in potato and tomato plants and suggest that, in general, mainly members of the subfamily I are involved in stress responses in both species. However, the differences found in the expression profiles between potato and tomato suggest divergent roles of PP2A in the plant defense mechanisms against stress in these closely related species.

Arabidopsis PHOSPHOTYROSYL PHOSPHATASE ACTIVATOR Is Essential for PROTEIN PHOSPHATASE 2A Holoenzyme Assembly and Plays Important Roles in Hormone Signaling, Salt Stress Response, and Plant Development

“…A null mutant of the PP2A-C2 gene in Arabidopsis is hypersensitive to both ABA and NaCl (Pernas et al, 2007). País et al (2009) demonstrated that transcripts of the subfamily I genes are down-regulated by cold in tomato (Solanum lycopersicum). Members of PP2Ac subfamily II are likely to be involved in auxin transport, as pp2a-c3c4 double mutants are not viable and have altered auxin distribution patterns (Ballesteros et al, 2013).…”

Serine/Threonine Protein Phosphatases type 2A and their roles in stress signaling

“…The inhibitor activates anti-fungal defense responses even in the absence of infection or elicitors in several plant species, such as soybean (Glycine max), 20 potato (Solanum tuberosum), tomato (Solanum lycopersicum), 8 tobacco (Nicotiana tabacum) 21 and opium poppy (Papaver somniferum), 22 suggesting the existence of active signaling pathways in the absence of stress that require continuous Ser/Thr phosphatase activity to remain inhibited.…”

“…4 Catalytic subunits can be grouped into two subfamilies, I and II. 4,7,8 PP2As have been implicated in auxin transport, 9,10 abscisic acid and ethylene signaling, [11][12][13] growth and development 14,15 and control of cytoskeletal structure. 16 Over the recent years, considerable effort has been devoted to the study of PP2A roles in plant stress responses.…”

Modulation of plant HMG-CoA reductase by protein phosphatase 2A

“…2 Cumulative evidence indicates that PP2A participates in the signaling of diverse stress conditions. 7 On the one hand, the transcript levels of particular PP2A subunits increase or decrease in response to biotic [36][37][38][39] or abiotic [39][40][41][42][43][44][45][46][47] challenges. On the other, PP2A activity or particular PP2A subunits participate as positive or negative transducers in the signaling of abscisic acid (ABA), [48][49][50] and ethylene, 51,52 in the response to cold 53 or drought, 45 or to ionic, osmotic and oxidative stress, 54 and in the defense against biotic challenge.…”