Red Light Induction of Gibberellin Synthesis in Leaves

D. M. REID; J. B. CLEMENTS; D. J. CARR

doi:10.1038/217580a0

Red- and Blue-Light Sensing in the Plant Pathogen Alternaria alternata Depends on Phytochrome and the White-Collar Protein LreA

mBio ◽

10.1128/mbio.00371-19 ◽

2019 ◽

Vol 10 (2) ◽

Cited By ~ 17

Author(s):

Olumuyiwa Igbalajobi ◽

Zhenzhong Yu ◽

Reinhard Fischer

Keyword(s):

Blue Light ◽

Alternaria Alternata ◽

Red Light ◽

White Collar ◽

Nuclear Accumulation ◽

Model Organisms ◽

Light Induction ◽

Content Type ◽

High Osmolarity ◽

Light Sensing

ABSTRACT The filamentous fungus Alternaria alternata is a common postharvest contaminant of food and feed, and some strains are plant pathogens. Many processes in A. alternata are triggered by light. Interestingly, blue light inhibits sporulation, and red light reverses the effect, suggesting interactions between light-sensing systems. The genome encodes a phytochrome (FphA), a white collar 1 (WC-1) orthologue (LreA), an opsin (NopA), and a cryptochrome (CryA) as putative photoreceptors. Here, we investigated the role of FphA and LreA and the interplay with the high-osmolarity glycerol (HOG) mitogen-activated protein (MAP) kinase pathway. We created loss-of function mutations for fphA, lreA, and hogA using CRISPR-Cas9 technology. Sporulation was reduced in all three mutant strains already in the dark, suggesting functions of the photoreceptors FphA and LreA independent of light perception. Germination of conidia was delayed in red, blue, green, and far-red light. We found that light induction of ccgA (clock-controlled gene in Neurospora crassa and light-induced gene in Aspergillus nidulans) and the catalase gene catA depended on FphA, LreA, and HogA. Light induction of ferA (a putative ferrochelatase gene) and bliC (bli-3, light regulated, unknown function) required LreA and HogA but not FphA. Blue- and green-light stimulation of alternariol formation depended on LreA. A lack of FphA or LreA led to enhanced resistance toward oxidative stress due to the upregulation of catalases and superoxide dismutases. Light activation of FphA resulted in increased phosphorylation and nuclear accumulation of HogA. Our results show that germination, sporulation, and secondary metabolism are light regulated in A. alternata with distinct and overlapping roles of blue- and red-light photosensors. IMPORTANCE Light controls many processes in filamentous fungi. The study of light regulation in a number of model organisms revealed an unexpected complexity. Although the molecular components for light sensing appear to be widely conserved in fungal genomes, the regulatory circuits and the sensitivity of certain species toward specific wavelengths seem different. In N. crassa, most light responses are triggered by blue light, whereas in A. nidulans, red light plays a dominant role. In Alternaria alternata, both blue and red light appear to be important. In A. alternata, photoreceptors control morphogenetic pathways, the homeostasis of reactive oxygen species, and the production of secondary metabolites. On the other hand, high-osmolarity sensing required FphA and LreA, indicating a sophisticated cross talk between light and stress signaling.

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External calcium requirements for light induction of chlorophyll accumulation and its enhancement by red light and cytokinin pretreatments in excised etiolated cucumber cotyledons

Planta ◽

10.1007/bf00197325 ◽

1995 ◽

Vol 196 (4) ◽

Author(s):

Carol Reiss ◽

SamuelI. Beale

Keyword(s):

Red Light ◽

Light Induction ◽

Chlorophyll Accumulation ◽

Cucumber Cotyledons ◽

External Calcium

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Persistence of Red Light Induction in Lettuce Seeds of Varying Hydration

PLANT PHYSIOLOGY ◽

10.1104/pp.53.3.503 ◽

1974 ◽

Vol 53 (3) ◽

pp. 503-506 ◽

Cited By ~ 8

Author(s):

Lars Loercher

Keyword(s):

Red Light ◽

Light Induction ◽

Lettuce Seeds

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Phytochromsystem und Lipochinonsynthese in den Plastiden etiolierter Hordeum-Keimlinge Phytochrome System and Synthesis of Lipoquinones in the Plastids of Etiolated Hordeum Seedlings

Zeitschrift für Naturforschung C ◽

10.1515/znc-1975-1-213 ◽

1975 ◽

Vol 30 (1-2) ◽

pp. 64-66 ◽

Cited By ~ 10

Author(s):

Hartmut K. Lichtenthaler ◽

Hans K. Kleudgen

Keyword(s):

Vitamin K ◽

Ground State ◽

Red Light ◽

Light Induction ◽

Short Pulses ◽

Concomitant Decrease ◽

Phytochrome System

Abstract Short pulses of red light induce in etiolated barley seedlings an enhanced synthesis of plastidic benzoquinones and vitamin K1 , which can be reverted by subsequent irradiation with short pulses of far-red. As compared to the dark there is more formation of plastoquinone-9 than α-tocopherol. The enhanced formation of vitamin K1 is coupled with a concomitant decrease in the level of the second naphthoquinone vitamin “K”. The data show that active phytochrome Pfr , also in its ground state, induces the light triggered lipoquinone synthesis which is connected to thylakoid formation. The red light induction of enhanced plastoquinone-9 synthesis cannot be fully reverted by subsequent far-red and seems to be a very fast phytochrome response.

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