Yan Hui, Xie Jian Bo, Ji Zhao Jun, Yuan Na, Tian Chang Fu, Ji Shou Kun, Wu Zhong Yu, Zhong Liang, Chen Wen Xin, Du Zheng Lin, Wang En Tao, Chen Wen Feng
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing, China.
State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing, China.
Front Microbiol. 2017 Nov 20;8:2282. doi: 10.3389/fmicb.2017.02282. eCollection 2017.
species are the main microsymbionts associated with the medicinal or sand-fixation plants and (AC) in temperate regions of China, while all the strains isolated from each of these plants could nodulate both of them. However, strain CCBAU01603 could nodulate AC plants and it's a high efficiency symbiotic and competitive strain with . Therefore, the common features shared by these symbiotic rhizobia in genera of and still remained undiscovered. In order to study the genomic background influencing the host preference of these AC symbiotic strains, the whole genomes of two ( CCBAU01550, CCBAU45272) and five representative strains ( CCBAU01583, CCBAU01570, CCBAU01502, CCBAU01399, and CCBAU01603) originally isolated from AC plants were sequenced, respectively. As results, type III secretion systems (T3SS) of AC rhizobia evolved in an irregular pattern, while an evolutionarily specific region including , T1SS, and a hydrogenase system was detected to be conserved in all these AC rhizobia. Moreover, was verified to be prevalently distributed in other AC rhizobia and was presumed as a factor affecting the nodule formation process. In conclusion, this research interpreted the multifactorial features of the AC rhizobia that may be associated with their host specificity at cross-nodulation group, including , T1SS as the possible main determinants; and , hydrogenase system, and T3SS as factors regulating the bacteroid formation or nitrogen fixation efficiency.
在中国温带地区，物种是与药用植物或固沙植物以及（AC）相关的主要微共生体，而从这些植物中分离出的所有菌株都能使它们两者结瘤。然而，菌株CCBAU01603能使AC植物结瘤，并且它是一种与……具有高效共生和竞争力的菌株。因此，这些共生根瘤菌在属和……中的共同特征仍未被发现。为了研究影响这些AC共生菌株宿主偏好的基因组背景，分别对最初从AC植物中分离出的两株（CCBAU01550，CCBAU45272）和五株代表性菌株（CCBAU01583，CCBAU01570，CCBAU01502，CCBAU01399和CCBAU01603）进行了全基因组测序。结果显示，AC根瘤菌的III型分泌系统（T3SS）以不规则模式进化，而在所有这些AC根瘤菌中检测到一个包括……、T1SS和一个氢化酶系统的进化特异性区域是保守的。此外，……被证实普遍分布于其他AC根瘤菌中，并被推测为影响结瘤形成过程的一个因素。总之，本研究解释了AC根瘤菌在交叉结瘤组中可能与其宿主特异性相关的多因素特征，包括……、T1SS可能是主要决定因素；以及……、氢化酶系统和T3SS作为调节类菌体形成或固氮效率的因素。
