耕種行為并非人類的專利,，研究人員發(fā)現(xiàn)一種真核微生物也會播種并收獲自己的食物——細菌,。
新一期Nature報告說，美國賴斯大學的研究人員發(fā)現(xiàn)一些盤基網(wǎng)柄菌具有這種農(nóng)業(yè)行為,。盤基網(wǎng)柄菌是黏菌的一種,，雖然名字中帶個“菌”字，卻并不是通常說的細菌,，而是屬于真核生物,。它通常以單細胞形態(tài)存在，以細菌為食,，但當某處的食物變得匱乏時,，大量盤基網(wǎng)柄菌就會聚集到一起，形成黏液狀的多細胞有機體,，集體遷徙到別的地方,。
過去人們一直認為盤基網(wǎng)柄菌只會這樣四處“游獵”，但本次研究發(fā)現(xiàn),，有的盤基網(wǎng)柄菌在找到可作為食物的細菌后,，并不將其完全吃掉，而是留下一部分作為“種子”,，在集體遷徙時也帶上這些“種子”,，到達新地方后再進行“播種”，以收獲更多細菌,。研究人員在報告中風趣地稱這些盤基網(wǎng)柄菌為“農(nóng)民”,。
領導研究的德布拉·布羅克說，盤基網(wǎng)柄菌有很多種,，研究只發(fā)現(xiàn)其中一部分具有這種行為,。具有這種能力的盤基網(wǎng)柄菌在食物稀缺環(huán)境下要比其他同類更具競爭力。（生物谷Bioon.com）
生物谷推薦原文出處：
Nature doi:10.1038/nature09668
Primitive agriculture in a social amoeba
Debra A. Brock,Tracy E. Douglas,David C. Queller& Joan E. Strassmann
Agriculture has been a large part of the ecological success of humans1. A handful of animals, notably the fungus-growing ants, termites and ambrosia beetles2, 3, 4, have advanced agriculture that involves dispersal and seeding of food propagules, cultivation of the crop and sustainable harvesting5. More primitive examples, which could be called husbandry because they involve fewer adaptations, include marine snails farming intertidal fungi6 and damselfish farming algae7. Recent work has shown that microorganisms are surprisingly like animals in having sophisticated behaviours such as cooperation, communication8, 9 and recognition10, 11, as well as many kinds of symbiosis12, 13, 14, 15. Here we show that the social amoeba Dictyostelium discoideum has a primitive farming symbiosis that includes dispersal and prudent harvesting of the crop. About one-third of wild-collected clones engage in husbandry of bacteria. Instead of consuming all bacteria in their patch, they stop feeding early and incorporate bacteria into their fruiting bodies. They then carry bacteria during spore dispersal and can seed a new food crop, which is a major advantage if edible bacteria are lacking at the new site. However, if they arrive at sites already containing appropriate bacteria, the costs of early feeding cessation are not compensated for, which may account for the dichotomous nature of this farming symbiosis. The striking convergent evolution between bacterial husbandry in social amoebas and fungus farming in social insects makes sense because multigenerational benefits of farming go to already established kin groups
