As hot as this year has been, it will probably have been the coldest year of the rest of our lives. Climate change is a reality and its effects are increasingly evident throughout the planet. And who are the living beings that come out worse off from this devastating situation? Those who in no way can escape the environmental changes that happen around them.
The longevity of trees and their life anchored to the same place imposes on them the need to face various stressful situations over time. These situations can be cyclical (climate changes throughout a year that are repeated over and over again) or specific, such as the attack of a plague, a heat wave or a period of extreme drought (although these extreme periods are being repeated several times per season in recent years).
Animals, unlike trees, have many resources to deal with these situations, from fight or flight to building tools and shelters. Animal survival lies to a large extent in experience, which allows us a better evaluation, anticipation and response to a risk. And this experience is based on memory.
Can plants show a similar behavior to guarantee the ultimate goal of any living being, that is, to ensure its survival?
Do plants have memory?
Plants do not have a complex memory based on a nervous system like animals, but have simpler systems. Any response at the molecular level is directed by the activation and deactivation of different genes (transcription). In recent years, it has been shown that environmental factors play a very important role in this process.
When a plant is subjected to stress, the molecular machinery coordinates the genes necessary to respond to that stress. Likewise, it modifies the transcription so that the cell can synthesize alternative forms of the proteins, called isoforms, which allow it to better withstand said stress.
This mechanism, known as splicing Alternatively, it is remembered for the transcription of a small number of genes up to six months after the stress ceases. The presence of these alternative forms allows plants to respond more quickly and efficiently when a similar stress situation is repeated, reducing the damage suffered. In other words, it is one of the strategies that plants trigger to memorize a stress and deal with that unfavorable environmental change.
Therefore, plants, like animals, are capable of perceiving, remembering, and learning from negative experiences in order to better deal with them the next time they occur. But this amazing learning capacity goes a step further since, under certain circumstances, parents are capable of transmitting part of this knowledge to their children in order to improve their chances of survival and competition against other plants through a better and faster response to stress.
transgenerational memory
As humans, our fathers and mothers accompany us during the first years of life, teaching us what is right and wrong and how we should act to avoid future problems. Something similar happens in the case of plants, but since they cannot communicate through words, they need to use other types of mechanisms to transmit their knowledge to their descendants.
A part of this knowledge is transmitted by maternal inheritance through the chloroplasts. These are the cell organelles in charge of carrying out photosynthesis and it has been shown that they are key in cell signaling processes and stress tolerance. They act as sensors that allow the progeny to better adapt to the environment from the moment of germination.
The offspring can thus survive their first months of life better than other competitors in their environment since they do not have to build the appropriate response to stress from scratch. That is, this received experience avoids an initial period of trial and error. The first time a stress is faced, the cell is not clear which are the best genes to “turn on” or their variants. splicing more accurate.
The increase in both efficiency and response speed will minimize the damage suffered by the plant when it faces its first stress, ensuring its survival and, therefore, that of the species.
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How do we study this phenomenon?
We have talked about specific mechanisms and routes as key elements to establish the bases of memory in plants. However, a living being cannot be understood in a compartmentalized way, but as a whole. Systems biology is responsible for this, which is based on the study of the different groups of molecules that are part of an organism to model its functioning.
The use of an integrative approach, combined with current analytical capacity – we can accurately study several thousand transcripts, proteins or metabolites in each experiment – allows us to do a kind of zoom biological to explain how plants function and respond to the environment based on the coordinated changes in their different physiological, genetic, epigenetic, proteomic and metabolomic pathways.
These works represent not only a great advance in basic science, discovering new mechanisms involved in the ability to adapt to the environment and the resilience of trees, but also in applied science. Many of these molecules can be used as biomarkers, that is, substances that indicate the biological state.
These biomarkers will allow the selection of seeds that can respond better to specific locations. In addition, they will provide essential information to assess the physiological state of forests in real time, thus becoming a key element in improving their management and sustainability in the current context of climate change.
But, despite the fact that most living beings are capable of facing adverse conditions and learning from them, as well as transmitting part of that knowledge to their descendants, systems biology has taught us two very important things:
Considering that we still do not have the capacity to colonize (and destroy) other planets, we must not forget our responsibility to future generations now that we still have time and can take giant steps towards a more sustainable world.
