Effects of global climate change on the roots of agricultural vegetables

Climate change is threatening agricultural crops and is jeopardizing food security. Droughts, floods, fluctuations in temperatures and changes in the composition of the soil, such as high salinity or nutrient deficiency, are some of the circumstances that negatively affect crops. They are called “abiotic stresses”, which are defined as the negative impact suffered by plants when they are exposed to unfavorable conditions caused by a non-living factor.

Plant roots are essential in detecting and responding to many of these abiotic stresses caused by climate change. That is where researchers from the Polytechnic University of Madrid (UPM) in Spain focus their study. “The root system plays an essential role, since it provides the water and nutrients necessary for plant growth and is therefore crucial for crop yields,” says María Sánchez, a researcher at the UPM and co-author of a study recently on the subject.

UPM scientists have carried out a bibliographic review that provides a synthesis of the most recent research on the effects of climate change on crop roots, at a morphological, physiological, molecular and genetic level. Most abiotic stresses produce the activation of molecular responses (“shared” responses or “shared responses”) in the root. Thus, these stresses alter the cell membrane, producing an ionic imbalance, which in turn causes the formation of reactive oxygen species (ROS).

“When these ROS accumulate at high levels, they are harmful to the cell. However, at adequate levels, they can act as signaling molecules, since they can activate calcium channels (Ca2+) in the plasma membrane”, explains the UPM researcher. When these channels are activated, they enter the cell and can react with other proteins present in the cytoplasm. These proteins are the map kinases (MAPK, MAPKK and MAPKK), which react with each other consecutively, forming what is called a cascade. This leads to the activation of different transcription factors in the cell nucleus, where the genetic material is found. These transcription factors, when activated, are capable of regulating the expression of some genes, thus modulating the genetic and molecular response to abiotic stresses, which in turn modulates the plant’s response.

For example, when plants are subjected to drought stress and high temperatures simultaneously, an increase in ROS levels has been reported. Since ROS are harmful to the cell, the plant quickly begins to synthesize antioxidant and protective compounds to counteract the damaging effects of these ROS. However, when the levels of these ROS are too high, the signaling cascade explained above begins, and the plant begins to synthesize hormones such as abscisic acid (ABA) or auxins, which play a very important role in the response of the ROS. plants to drought and high temperatures. In this way, the plant begins to respond to these stresses.

However, if the plant were to encounter drought and high soil salinity, the cellular response would be similar to that described but with some differences, since the transcription factors activated in the nucleus would regulate genes different from the previous ones and different mechanisms of activation would be activated. adaptation, which would be specific to this type of response.

Estate. (Photo: Amazings/NCYT)

“Roots are an organ with great potential to provide tools for adaptation to climate change and could be key when looking for new genetic resources to improve crop resistance to the adverse conditions of climate change,” underlines María Sánchez.

On the other hand, the study also highlights the importance of addressing the analysis of the effects of abiotic stresses in a combined way, given the complexity of climate change. Traditionally, most of the research related to the effects of climate change on agricultural crops has focused on studying the effect of abiotic stresses in isolation, when abiotic stresses usually occur together in real life.

For example, droughts are often accompanied by high temperatures or increased salinization of the soil, aggravating the negative effect of these stresses on crop productivity. In addition, researchers have observed that the effects on crops of two or more simultaneous abiotic stresses differ from the effects of these same stresses when they occur individually.

“The effects of climate change on crops are more complex than we think,” says the UPM researcher. Our objective, he concludes, is “to provide a systematic review of the effects of the combination of abiotic stresses produced by climate change on the root system of crops, which will not only facilitate future research, but also raise awareness of the urgency of finding new solutions.” to achieve the adaptation of crops to climate change and improve global food security”.

The study is titled “Effects of Combined Abiotic Stresses Related to Climate Change on Root Growth in Crops”. And it has been published in the academic journal Frontiers in Plant Science. (Source: UPM)