Franco Ernesto, Troncozo María I, Baez Margot, Mirífico María V, Robledo Gerardo L, Balatti Pedro A, Saparrat Mario C N
Cátedra de Fitopatología-CIDEFI, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata (UNLP), 60 y 119, CC 31, 1900, La Plata, Argentina.
Cátedra de Microbiología Agrícola, Facultad de Ciencias Agrarias y Forestales, UNLP, 60 y 119, 1900, La Plata, Argentina.
Folia Microbiol (Praha). 2018 Mar;63(2):169-179. doi: 10.1007/s12223-017-0541-8. Epub 2017 Sep 10.
The role of microorganisms in litter degradation in arid and semi-arid zones, where soil and water salinization is one of the main factors limiting carbon turnover and decay, remains obscure. Heterostachys ritteriana (Amaranthaceae), a halophyte shrub growing in arid environments such as "Salinas Grandes" (Córdoba, Argentina), appears to be the main source of organic matter in the area. Little is known regarding the microorganisms associated with H. ritteriana, although they are a potential source of enzymes such as cellulolytic ones, which might be important in biotechnological fields such as bioethanol production using ionic liquids. In the present study, by studying the microbiota growing on H. ritteriana leaf litter in "Salinas Grandes," we isolated the cellulolytic fungus Fusarium equiseti LPSC 1166, which grew and degraded leaf litter under salt stress. The growth of this fungus was a function of the C substrate and the presence of NaCl. Although in vitro the fungus used both soluble and polymeric compounds from H. ritteriana litter and synthesized extracellular β-1,4 endoglucanases, its activity was reduced by 10% NaCl. Based on these results, F. equiseti LPSC 1166 can be described as a halotolerant cellulolytic fungus most probably playing a key role in the decay of H. ritteriana leaf litter in "Salinas Grandes."
在干旱和半干旱地区，土壤和水的盐碱化是限制碳周转和腐烂的主要因素之一，微生物在凋落物降解中的作用仍不清楚。异穗藜（苋科）是一种生长在干旱环境中的盐生灌木，如阿根廷科尔多瓦的“大盐湖”，它似乎是该地区有机物质的主要来源。关于与异穗藜相关的微生物知之甚少，尽管它们可能是纤维素酶等酶的潜在来源，这些酶在生物技术领域（如使用离子液体生产生物乙醇）可能很重要。在本研究中，通过研究在“大盐湖”中生长在异穗藜落叶上的微生物群，我们分离出了耐盐纤维素分解真菌尖孢镰刀菌LPSC 1166，它在盐胁迫下生长并降解落叶。这种真菌的生长是碳底物和氯化钠存在的函数。尽管在体外该真菌利用了异穗藜落叶中的可溶性和聚合物化合物并合成了细胞外β-1,4内切葡聚糖酶，但其活性在10%氯化钠存在下降低。基于这些结果，尖孢镰刀菌LPSC 1166可被描述为一种耐盐纤维素分解真菌，很可能在“大盐湖”中异穗藜落叶的腐烂中起关键作用。
