The long-term response to fluctuating light quality is an important and distinct light acclimation mechanism that supports survival of Arabidopsis thaliana under low light conditions

Plants that develop under low intensity light (LL) often display a phenotype known as the "shade tolerance syndrome (STS)". This syndrome is similar to the phenotype of plants in the juvenile phase of shoot development, but the basis for this similarity is unknown. We tested the hypothesis that the STS is regulated by the same mechanism that regulates the juvenile vegetative phase by examining the effect of LL on rosette development in Arabidopsis thaliana. We found that LL prolonged the juvenile vegetative phase and that this was associated with an increase the expression of the master regulators of vegetative phase change, miR156 and miR157, and a decrease in the expression of their SPL targets. Exogenous sucrose partially corrected the effect of LL on seedling development and miR156 expression. Our results suggest that the response of Arabidopsis to LL is mediated by an increase in miR156/miR157 expression and by factors that repress SPL gene expression independently of miR156/miR157, and is caused in part by a decrease in carbohydrate production. The effect of LL on vegetative phase change does not require the photoreceptors and transcription factors responsible for the shade avoidance syndrome, implying that light intensity and light quality regulate rosette development by different pathways.

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Environmental Signal-Dependent Regulation of Flowering Time in Rice

International Journal of Molecular Sciences ◽

10.3390/ijms21176155 ◽

2020 ◽

Vol 21 (17) ◽

pp. 6155

Author(s):

Jae Sung Shim ◽

Geupil Jang

Keyword(s):

Arabidopsis Thaliana ◽

Environmental Factors ◽

Flowering Time ◽

Molecular Mechanisms ◽

Light Quality ◽

Critical Event ◽

Light Conditions ◽

Environmental Signals ◽

Internal Time ◽

Light Quantity

The transition from the vegetative to the reproductive stage of growth is a critical event in the lifecycle of a plant and is required for the plant’s reproductive success. Flowering time is tightly regulated by an internal time-keeping system and external light conditions, including photoperiod, light quality, and light quantity. Other environmental factors, such as drought and temperature, also participate in the regulation of flowering time. Thus, flexibility in flowering time in response to environmental factors is required for the successful adaptation of plants to the environment. In this review, we summarize our current understanding of the molecular mechanisms by which internal and environmental signals are integrated to regulate flowering time in Arabidopsis thaliana and rice (Oryza sativa).

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Wind-evoked anemotropism affects the morphology and mechanical properties of Arabidopsis

Journal of Experimental Botany ◽

10.1093/jxb/eraa541 ◽

2020 ◽

Author(s):

Oleksandr Zhdanov ◽

Michael R Blatt ◽

Hossein Zare-Behtash ◽

Angela Busse

Keyword(s):

Mechanical Properties ◽

Arabidopsis Thaliana ◽

Mechanical Stress ◽

Opposite Direction ◽

Mechanical Stimulus ◽

Mechanical Stimuli ◽

Tissue Organization ◽

Term Response ◽

Morphology And Mechanical Properties

Abstract Plants are known to exhibit a thigmomorphogenetic response to mechanical stimuli by altering their morphology and mechanical properties. Wind is widely perceived as mechanical stress and in many experiments its influence is simulated by applying mechanical perturbations. However, it is known that wind-induced effects on plants can differ and at times occur even in the opposite direction compared with those induced by mechanical perturbations. In the present study, the long-term response of Arabidopsis thaliana to a constant unidirectional wind was investigated. We found that exposure to wind resulted in a positive anemotropic response and in significant alterations to Arabidopsis morphology, mechanical properties, and anatomical tissue organization that were associated with the plant’s strategy of acclimation to a windy environment. Overall, the observed response of Arabidopsis to wind differs significantly from previously reported responses of Arabidopsis to mechanical perturbations. The presented results suggest that the response of Arabidopsis is sensitive to the type of mechanical stimulus applied, and that it is not always straightforward to simulate one type of perturbation by another.

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