1086 joke

In "Ethylene, a Magic Gas | Part I", we learned that since ancient times, human beings have used ethylene to ripen fruits. It was not until the early 20th century that people began to study the relationship between ethylene and fruit ripening by scientific methods, which proved that ethylene is a natural product of plants. The road of ethylene scientific research began.

Although it has been found that fruit ripening is related to ethylene, the causal relationship is not clear. As we all know, every cause has its result. If the causal relationship is reversed, it is not only a serious logical error, but also a joke. For example, if you eat a rotten egg, which causes you to have diarrhea, then eating a rotten egg is the reason, and diarrhea is the result, which makes sense logically; And if the cause and effect are reversed, you have diarrhea, which makes you eat a rotten egg. It doesn't make sense logically unless you have a special hobby. O(∩_∩)O~

The causal relationship between fruit ripening and ethylene production is similar. If the fruit ripens first and is accompanied by ethylene production, then ethylene production is the fruit. If the increase of ethylene content leads to the ripening of fruit, then the production of ethylene is the reason. There is an essential difference between the two.

We know that in causality, there is cause and effect. Therefore, the key to answer the causal relationship between fruit ripening and ethylene production is to find out whether ethylene production is before or after fruit ripening. Because the yield of ethylene is extremely low in the process of fruit ripening, and the technology of detecting ethylene content was extremely primitive and backward at that time, this problem has not been solved until the gas chromatography and flame ionization detector were applied to the determination of ethylene in the 1960s, which greatly improved the sensitivity and accuracy of ethylene detection. With the help of these two technologies, researchers can monitor ethylene production in real time and study which comes first, ethylene production or fruit ripening. The final results showed that ethylene began to be synthesized in large quantities before fruit ripening, which indicated that ethylene was the cause of inducing fruit ripening.

Causality can be used by us. Just as it is clear that eating rotten eggs will lead to diarrhea, we can reduce the chance of diarrhea by avoiding eating rotten eggs, just as it is clear that the causal relationship between ethylene and fruit ripening, people naturally think of artificially regulating fruit ripening by regulating ethylene and related components. As a result, some plant growth regulators related to ethylene, such as ethephon, 1- methylcyclopropene (1-MCP), were gradually discovered and applied in production practice, which greatly reduced the economic losses caused by fruit rot.

Although the relationship between ethylene and fruit ripening has been known, it has been widely used in postharvest treatment of fruits. However, ethylene is still a mysterious black box. People only know it, but they don't know why. Among them, the first question is how this gas with magical function is produced in living beings. In 1960s, Lieberman and Mapson treated mature fruits with methionine labeled with 14C, and found radiation signals in the produced ethylene gas, which proved that methionine was the precursor of ethylene synthesis.

The main contribution of ethylene biosynthesis comes from Professor Yang Xiangfa of the University of California, Davis. Professor Yang Xiangfa and his colleagues revealed the pathway of ethylene biosynthesis through years of systematic research, pointing out that the direct precursor of ethylene synthesis is 1- aminocyclopropane-1- carboxylic acid (ACC). In order to commemorate Professor Yang Xiangfa's great contribution to the study of ethylene biosynthesis, the scientific community named the methionine cycle in the process of ethylene synthesis as Young's cycle.

The biosynthetic pathway of ethylene has been put in front of people. The next question is how organisms recognize ethylene and adjust plants to respond accordingly. This is the so-called signal transduction pathway. Since 1980s and 1990s, Arabidopsis thaliana, as a model plant, has been gradually applied to scientific research. Like pea yellowing seedlings, Arabidopsis yellowing seedlings also show a typical "triple response" (roots and hypocotyls become shorter and thicker, and hooks are formed at the top). Subsequently, the emergence and perfection of artificial mutation, map-based cloning and genetic transformation of Arabidopsis thaliana brought dawn to the study of ethylene signal transduction.

Using artificial mutation technology and triple response, researchers screened out a series of Arabidopsis mutants with abnormal triple response, which mainly showed two types: insensitivity to ethylene treatment (after ethylene treatment, there was still a long hypocotyl and no hook root) and constitutive ethylene reaction (when ethylene treatment was not used, triple response appeared). Subsequently, the mutant genes were identified by map-based cloning technology, and the upstream and downstream relationships of ethylene signal-related genes were identified by genetic analysis. Most of the work was done by JosephEcker Lab, which was introduced in my other blog post "The Great Cross-border God Joseph Ecker".

In recent thirty years, with the joint efforts of scientists from all over the world, the main components of ethylene signal transduction pathway (not listed here, but will be introduced later) have been constructed and gradually applied in production practice to regulate the growth and development of plants and increase the stress resistance of plants to better meet human needs. In recent years, with the rapid development of science and technology, the new functions of ethylene in plant growth and development have been gradually discovered, new components in ethylene signal transduction pathway have been gradually cloned and identified, and the interaction network between ethylene and other plant hormones has been gradually revealed.

Looking back at history, we are in the best time to do scientific research, and various new technologies and methods emerge one after another. Our era, like the scorching sun at noon, is radiant and passionate. Ethylene, such an ancient and mysterious gas, is bound to play an increasingly important role in the stage of human history.

1. A century of ethylene research

2./ Plant Physiology -2/ Plant Hormones/Ethylene-History-Functions and Uses /44735

4./ Article/Origin of Fruit Ripening/

5. Bachelor of Arts in Brick, Master of Arts in estelle, Master of Arts in Somerville and Master of Arts in Kende (1988). A dominant mutation in Arabidopsis thaliana is insensitive to ethylene. Science 241:1086-1089

6. Yang, Lu, X, Ma, B, Chen, S, Y. Zhang, J. S. (20 15). Ethylene signaling in rice and Arabidopsis: conservative and divergent aspects. Molecular Plants, Vol.8, No.4, 495-505.