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Forests accumulate and store large amounts of carbon (C), and a sub 2 i) m0 `& A& u) H* S- ~stantial fraction of this stock is contained in deadwood. This transient pool is subject; i2 `+ P$ k% l& d7 R( A0 s4 T
to decomposition by deadwood-associated organisms, and in this process it contrib1 ?: k# Q; _% k
utes to CO2 ; }( [; A8 y E, X- s2 C( b
emissions. Although fungi and bacteria are known to colonize dead ! d* i4 Y7 e7 |9 Jwood, little is known about the microbial processes that mediate carbon and nitro3 N; w5 C/ c" {# A$ c K9 }# @
gen (N) cycling in deadwood. In this study, using a combination of metagenomics,. p$ T D$ u- ~. q8 U: S' u' M0 ^
metatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom 2 o2 M$ v6 R6 f; l0 Eposition of deadwood reflflects the complementary roles played by fungi and bacteria.8 n3 Z" k8 C2 P. ] |$ M) r
Fungi were found to dominate the decomposition of deadwood and particularly its re0 M, d8 `" ?+ J( K* o5 u) K
calcitrant fractions, while several bacterial taxa participate in N accumulation in dead + r# R4 _' g. i$ k: T: cwood through N fifixation, being dependent on fungal activity with respect to deadwood/ b% e- h+ V4 Q+ C+ v$ w$ w+ P3 o6 X
colonization and C supply. Conversely, bacterial N fifixation helps to decrease the con! c* [. H1 v/ [) a
straints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation , T) [) |, H9 c4 m/ t% xthat are a result of a joint action of deadwood bacteria and fungi may be signifificant for 3 z; X) ?$ X, ~6 n+ q, Bnutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead8 e" c* Q5 t5 z" f V: v p+ G/ d5 ^
wood retention may help to improve the nutritional status and fertility of soils./ f; V' @9 c( d# ?/ @
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发表于 2021-2-5 07:42
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