为什么裂褶菌等四极性真菌拥有数以万计种交配型？其分子识别机制是什么？
Why do tetrapolar fungi such as Schizophyllum commune possess tens of thousands of mating types, and what molecular recognition underlies this?
裂褶菌等四极性担子菌由两个复等位基因座决定性别：A座编码同源域转录因子，B座编码信息素及其G蛋白偶联受体。仅当两座等位基因均不同时，交叉的信息素—受体识别才启动双核化发育并形成锁状联合。负频率依赖选择偏爱罕见等位基因，使每个座位积累数百种特异性，自由组合令裂褶菌拥有逾2.8万种交配型，最大化异宗交配、避免近亲衰退。
In tetrapolar basidiomycetes such as Schizophyllum commune, sex is governed by two multiallelic loci: the A locus encodes homeodomain transcription factors, while the B locus encodes pheromones and their G-protein-coupled receptors. Only when both loci differ between partners does reciprocal pheromone-receptor recognition trigger dikaryotization with clamp connections. Negative frequency-dependent selection favors rare alleles, letting hundreds of specificities accumulate per locus—together yielding more than 28,000 mating types in S. commune, maximizing outcrossing and averting inbreeding depression.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Casselton L.A. & Olesnicky N.S.《Molecular genetics of mating recognition in basidiomycete fungi》,Microbiology and Molecular Biology Reviews,1998年第62卷第55-70页
Casselton L.A. & Olesnicky N.S., "Molecular genetics of mating recognition in basidiomycete fungi," Microbiology and Molecular Biology Reviews 62:55-70 (1998)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1128/mmbr.62.1.55-70.1998：Molecular Genet
#交配型 #担子菌门 #频率依赖选择
为什么菌丝状的体型让真菌成为特别高效的分解者？
Why does the filamentous (hyphal) body plan make fungi exceptionally efficient decomposers?
真菌靠菌丝顶端持续延伸，能钻入枯枝落叶和木材等基质内部。菌丝向外分泌纤维素酶、木质素降解酶等胞外水解酶，把大分子聚合物切成可溶性小分子后再吸收；庞大的分支网络还提供了巨大的吸收表面积。这种先体外消化、后吸收的策略使真菌能攻克多数生物无法利用的木质纤维素，因此在陆地碳循环中充当关键分解者。
Hyphae extend continuously at their tips, penetrating deep into substrates such as leaf litter and wood. They secrete extracellular hydrolytic enzymes, including cellulases and lignin-degrading enzymes, that cut large polymers into soluble fragments before absorbing them, while the branching mycelium offers an immense absorptive surface. This digest-outside-then-absorb strategy lets fungi unlock lignocellulose that few other organisms can exploit, making them pivotal decomposers in the terrestrial carbon cycle.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Webster J. 与 Weber R.W.S. 合著 Introduction to Fungi 第3版，剑桥大学出版社，2007年
Webster & Weber, Introduction to Fungi, 3rd ed., Cambridge University Press, 2007
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL16985148W：Introduction to fungi（
#菌丝生长 #胞外酶 #分解作用 #碳循环
为什么大多数陆生植物的生存离不开菌根真菌？
Why do most land plants depend on mycorrhizal fungi for survival?
约八成陆生植物的根与真菌结成菌根共生体。真菌菌丝远比根毛纤细，可伸入根系养分耗竭区之外，将磷、锌等难获取的矿质养分持续送入根细胞，植物则把光合产物糖类供给真菌。这种养分互换大幅提升了植物在干旱贫瘠土壤中的存活与生长能力，也被认为在植物登陆初期发挥了关键作用。
About 80 percent of land plants form mycorrhizal partnerships with fungi. Hyphae are far finer than root hairs and reach beyond the nutrient-depletion zone around roots, funneling scarce minerals such as phosphate into root cells, while the plant hands over sugars from photosynthesis. This nutrient trade greatly improves plant performance in dry, infertile soils and is thought to have been crucial when plants first colonized land.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Smith与Read，《Mycorrhizal Symbiosis》第3版，Academic Press，2008年
Smith & Read, Mycorrhizal Symbiosis, 3rd ed., Academic Press, 2008
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780080559346 (2008)
#菌根 #互利共生 #磷吸收