A research group led by Kazutaka Yoshida, a second-year doctoral student at Kagoshima University (in addition, Kyushu Okinawa Agricultural Research Center, Saga University, Agricultural Research Organization), said that symbiotic bacteria are caused by breeding strains of Himetobiunka, which is a pest such as paddy rice. We confirmed the existence of a resistance gene to "male killing" and clarified its genetic pattern.

 In some populations of Himetobiunka, in addition to the symbiotic bacterium Wolbachia, which performs a reproductive operation called "cytoplasmic incompatibility" (modifying reproduction conveniently), a symbiotic symbiosis that performs "male killing" (a phenomenon that kills only the male host). Bacterial spiroplasma is infected.In spiroplasma infection, males die between hatching and emergence, and the sex ratio is large and biased toward females.

 Since male killing is disadvantageous to the survival of the host, it is said that "resistance" that nullifies male killing appears rapidly in nature.However, it is very difficult to observe the evolutionary process of insects for which male killing has been disabled because there is no abnormality in appearance, and only two cases have been reported in which resistance to male killing emerged and spread among insects.

 This time, one of the breeding strains of Himetobiunka was found to have a sex ratio of 1: 1 despite being infected with spiroplasma.As a result of mating experiments, it was found that this "male killing resistance" is a trait that is overtly (dominantly) expressed in simple Mendelian inheritance.This is the world's first report of resistance to male killing in insects of the order Hemiptera and resistance to "late-type male killing" in which males die during the larval stage.

 Currently, the identity of the male killing resistance gene and its mechanism are unknown, but this discovery will be an important finding for elucidating the interaction between male killing bacteria and host insects, and will be detailed in future research on reproductive manipulation by symbiotic bacteria. It is expected that it will be applied to pest control in the future.

Paper information:[Proceedings of the Royal Society B: Biological Sciences] Silence of the killers: discovery of male-killing suppression in a rearing strain of the small brown planthopper, Laodelphax striatellus

Kagoshima University

Aiming to become a glocal education and research center that flies from southern Kyushu to the world

Kagoshima University has nine faculties and nine graduate schools, with approximately 9 undergraduate students and approximately 9 graduate students (including approximately 9,000 international students), for a total of approximately 2,000 students.We strive to discover the potential of each student and to develop their aptitude, and provide a wide range of liberal arts education and advanced specialized education, as well as […].

Saga University

Aspirations, challenges, and the future.Foster attractive human resources who can play an active role in a diversifying future

Saga University is a national university that was established in 1949 with the former Saga University established in 1976 and the Saga Medical University established in 2004 as the parent body. It has 6 faculties and 6 graduate schools, and about 5,800 undergraduate students are enrolled.Along with acquiring knowledge in specialized fields, a wide range of education, cooperation with others, and independent learning […]

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