Scientists have discovered a new gene that regulates the development of stomata. This gene is called HIC and is found in the Arabidopsis thaliana plant. Researches have found that plants with a dominant allele of the gene do not develop stomata at all, while the wild type recessive allele has a big increase in stomatal development. The researchers believe that the gene is involved in plants’ response to rising CO2 levels in the atmosphere.
Coronatine-biosynthesis-defective (cor) mutant
A plant’s stomata respond to both live bacteria and PAMPs by closing and opening. A plant’s guard cells use coronatine as a defense against these agents. Hence, if a plant is missing stomata, it would become susceptible to secondary infections, such as aphids.
A plant’s response to rising CO2 levels is largely determined by its response to its environment. Hence, a plant’s response to changing CO2 levels may be partly governed by its genetics. However, it is not known whether a plant would be able to respond to changing CO2 levels without stomata.
A plant’s stomata may be responsible for regulating plant hormones. An example of this is the F-box protein, which binds to JA-Ile, which is a plant hormone. This protein is degraded by the 26S proteasome in a SCFCOI1-dependent manner. COI1 also interacts with the JAZ protein, which is a repressor of the JA signaling pathway. Both proteins have been shown to interact in yeast cells when JA-Ile (108) or COR are present.
The stomata are composed of specialized epidermal cells called guard cells that regulate the rate of water loss and water exchange. They can change size in response to a variety of environmental stimuli. Changes in light intensity, CO2 concentration, and relative humidity all affect stomatal movement. In addition, the presence of abscisic acid plays a vital role in the signaling of guard cells. It is also responsible for the regulation of stomatal closure under drought stress.
The stomata also play a role in plant-fungal interactions. A transgenic plant called Nicotiana tabacum recognizes a fungal defense elicitor, which activates a series of outward-rectifying K+ channels and inhibits inward-rectifying K+ channels. However, the biological significance of this response is not fully understood.