Tag­ging Ac­tive Mi­crobes

Note­wor­thy

Se­quence analy­sis pro­vides a rel­a­tively straight­for­ward method for iden­ti­fy­ing the tax­on­omy and di­ver­sity of mi­crobes in a com­plex en­vi­ron­men­tal sam­ple. But it is a far more dif­fi­cult task to dis­tin­guish meta­bol­i­cally ac­tive from dor­mant mi­cro­bial mem­bers within a com­mu­nity. Yet this dis­tinc­tion may prove key to un­der­stand­ing which mi­crobes are rel­e­vant for com­mu­nity as­sem­bly dur­ing col­o­niza­tion and for pro­vid­ing func­tional ben­e­fits. 

Ex­per­i­men­tal de­sign for prob­ing mi­cro­bial ac­tiv­ity and com­po­si­tion across a plant-soil gra­di­ent. Repli­cates of Tri­folium in­car­na­tumwere grown in a green­house (A), and sam­ples were taken (B) for dif­fer­ent analy­sis ©. For more info to go source. Fron­tispiece: Tri­folium in­car­na­tum. © Greg Pe­ter­son, source.

In a re­cent re­port, sci­en­tists from Penn­syl­va­nia State Uni­ver­sity em­ployed a method­ol­ogy named BONCAT (Biorthog­o­nal Non-Canon­i­cal Amino Acid Tag­ging) to iden­tify meta­bol­i­cally ac­tive mi­crobes that could po­ten­tially pro­vide plant-ben­e­fi­cial func­tions. By la­belling mi­crobes across a gra­di­ent, from soil to roots, and cou­pling these re­sults to Flow Cy­tome­ter Ac­ti­vated Cell Sort­ing (FACS) and 16S rRNA am­pli­con se­quenc­ing analy­sis, they were able to probe for mi­cro­bial ac­tiv­ity on and in plant roots. Mi­cro­bial ac­tiv­ity was 10 times higher in­side plant tis­sues when com­pared to the soil and was also as­so­ci­ated with suc­cess­ful col­o­niza­tion of the in­ter­nal plant tis­sues – the en­dos­phere. 

Why is this in­ter­est­ing? These find­ings in­di­cate that meta­bol­i­cally ac­tive mi­crobes are im­por­tant for as­so­ci­a­tion with plants. But more im­por­tantly, this can be lever­aged to pro­mote ac­tive mi­cro­bial com­mu­ni­ties from a na­tive soil to im­prove agri­cul­tural pro­duc­tiv­ity and sus­tain­abil­ity.