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AM真菌在生态系统中的作用* m' A6 k7 i' g( ]; |
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Forests accumulate and store large amounts of carbon (C), and a sub ( B% V$ [7 D$ h& B7 P" S5 J* Zstantial fraction of this stock is contained in deadwood. This transient pool is subject6 p- ^9 w4 U! a
to decomposition by deadwood-associated organisms, and in this process it contrib 0 b+ v+ I1 s; G1 W' cutes to CO2 6 q& s: V2 q3 pemissions. Although fungi and bacteria are known to colonize dead 8 E4 n# o2 E* J$ q+ Iwood, little is known about the microbial processes that mediate carbon and nitro ' m& A; T2 x s; N& L- T9 Hgen (N) cycling in deadwood. In this study, using a combination of metagenomics, k4 I! z" \( {' |! F
metatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom9 W' \6 L% c+ ?6 ^
position of deadwood reflflects the complementary roles played by fungi and bacteria.9 {% V1 _2 }+ x& |$ r8 ]" `
Fungi were found to dominate the decomposition of deadwood and particularly its re 7 Q ~# L0 U" g8 j2 n8 ocalcitrant fractions, while several bacterial taxa participate in N accumulation in dead 7 u, t& N' `8 }: V3 w* Y' y! wwood through N fifixation, being dependent on fungal activity with respect to deadwood 3 b/ m0 m* l8 |0 ~3 i7 V6 Ccolonization and C supply. Conversely, bacterial N fifixation helps to decrease the con* b* t3 {& e1 x8 Z6 E
straints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation' i, M& ]/ U! ~, l& \) D' D h
that are a result of a joint action of deadwood bacteria and fungi may be signifificant for / k" x2 e/ g. y* [nutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead0 p8 z$ Z9 f2 _0 {4 t7 z6 U4 }
wood retention may help to improve the nutritional status and fertility of soils.8 n5 J4 Y0 I+ L3 q8 b
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发表于 2021-2-5 07:42
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