2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
The fruit of the citron palmate (Cítrus médica var. Sarcodáctylis), known as the "hand of Buddha".
Researchers have traced the distribution of citrus fruits for their "acid-free" phenotype, according to Current Biology. As the authors of the article found out, the acidity of citrus fruits is associated with the Noemi gene. The varieties of the "Buddha's hand" citron, which were grown in ancient China, and the citron, which was grown in the Eastern Mediterranean, have a gene variant that reduces its activity and reduces the sour taste of citrus fruits. The Jews used citron during the harvest festival and, along with the Jewish communities, the plant appears to have spread throughout the Mediterranean.
Presumably, citrus fruits appeared about eight million years ago in Southeast Asia - in the territory of modern Myanmar, in southwestern China and in northeastern India. They began to cultivate at least three thousand years ago. Despite the great variety of species, genetics have identified four original species, including citron (Cítrus médica), which gave rise to other citrus varieties.
Many citrus fruits produce anthocyanins, pigments that color the flowers, leaves, and seeds of these plants, and are also associated with the sour taste of the fruit. The production of anthocyanins is associated with the activity of the Ruby gene, which encodes one of the proteins that regulate RNA synthesis. Mutations in this gene lead to the appearance of the so-called “acid-free” phenotype of citrus fruits: a decrease in the sour taste of fruits and a change in the color of their leaves, seeds and flowers.
Geneticists from the UK, USA, Italy and France, led by Cathie Martin of the John Innes Center in Norwich, studied the synthesis of anthocyanins in citrus fruits to understand their taxonomy and to find out how the domestication of these plants took place. They found that some varieties of citrus fruits lost the ability to produce anthocyanins, and their fruits became less acidic despite the presence of the "wild-type" Ruby gene, that is, in which there were no mutations that change its activity. As it turned out, the production of anthocyanins, in addition to the Ruby gene, is influenced by a gene that scientists called Noemi, the functions of which were previously unknown. It encodes a protein that regulates the biosynthesis of anthocyanins. The authors of the article found that several varieties of citrus fruits with an "acid-free" phenotype, including citron, sweet limes and oranges, have mutations in the Noemi gene that "turn off" its activity. In particular, the scientists discovered the n DEL3 `mutation - a deletion (absence) of the region encoding the last 275 amino acids of the protein.
The researchers found that the n DEL3 `mutation arose a long time ago. It is found in the palm citron (Cítrus médica var. Sarcodáctylis), the “hand of Buddha”, which is so called for the characteristic shape of the fruit, and which was grown in ancient India and China. In addition, the etrog has this mutation - a variety of citron, which in the Jewish tradition is one of the symbols of the Sukkot harvest festival and which the ancient Jews began to use in the 6th century BC. Later, Jewish communities played an important role in the spread of citron throughout the Mediterranean. “Some people think it was a recent mutation that originated in Corsica or somewhere in the Mediterranean, but we found that it is not new,” explains one of the study's authors, Eugenio Boutelli of the John Innes Center. "It is an ancient mutation that is present in the finger citron known as the Buddha's hand and [citron] used in the Sukkot celebrations."
Earlier, Israeli archaeobotanist Daphne Langgut reconstructed the order in which a particular type of citrus appeared in the Mediterranean and the way they entered the region. The citron was the first to appear in Palestine together with the Persians, later the ancient Romans "got acquainted" with it. The next to appear in the Mediterranean was lemon, which was brought by the Romans, and almost a thousand years later - bitter oranges, limes and pomelo.