A Proteome map of a quadruple photoreceptor mutant sustains its severe photosynthetic deficient phenotype Journal of Plant Physiology

ANA ROMINA FOX; MARÍA LAURA BARBERINI; EDMUNDO LEONARDO PLOSCHUK; JORGE PROMETEO MUSCHIETTI ; MARIA AGUSTINA MAZZELLA

JOURNAL OF PLANT PHYSIOLOGY

ELSEVIER GMBH

Año: 2015 vol. 185 p. 13 - 23

0176-1617

Light is the environmental factor that most affects plant growth and development through its impact on photomorphogenesis and photosynthesis. A quadruple photoreceptor mutant lacking four of the most important photoreceptors in plants, phytochromes A and B (phyA, phyB) and cryptochromes 1 and 2 (cry1, cry2), is severely affected in its growth and development. Previous evidences suggest that, in addition to a photomorphogenic disorder, the phyA phyB cry1 cry2 quadruple mutant might have severe photosynthetic ability alterations. Here we investigated the photosynthetic processes that are altered in the quadruple mutant and performed a proteomic profiling approach to identify the involved proteins. phyA phyB cry1 cry2 quadruple mutants showed reduced leaf area and reduced total chlorophyll content. Photosynthetic rates at high irradiances were reduced about 65% compared to the wild type (WT). Light saturated photosynthesis and the response of net CO2 exchange to low and high internal CO2 concentrations suggest that the levels or activity of the components of the Calvin cycle and electron transport might be reduced in the quadruple mutant. Consistently, most of the under expressed proteins in the phyA phyB cry1 cry2 quadruple mutant had chloroplastic localitation and components of the Calvin cycle and the light reaction centers were overrepresented. Additionally, Rubisco expression, the first enzyme responsible for carbon fixation, was three fold reduced in phyA phyB cry1 cry2 quadruple mutants. Together these results highlight the importance of phytochrome and cryptochrome families in the proper autotrophy establishment in plants and suggest that limitations in Rubisco, the Calvin Cycle and electron transport that affects RuBP regeneration reduced photosynthetic capacity in phyA phyB cry1 cry2 quadruple mutants at high irradiances.