title: Overexpression of a fungal β-mannanase from Bispora sp. MEY-1 in maize seeds and enzyme characterization.
abstract: BACKGROUND
  Mannans and heteromannans are widespread in plants cell walls and are well-known as anti-nutritional factors in animal feed. To remove these factors, it is common practice to incorporate endo-β-mannanase into feed for efficient nutrition absorption. The objective of this study was to overexpress a β-mannanase gene directly in maize, the main ingredient of animal feed, to simplify the process of feed production.
  
  
  RESULTS
  The man5A gene encoding an excellent β-mannanase from acidophilic Bispora sp. MEY-1 was selected for heterologous overexpression. Expression of the modified gene (man5As) was driven by the embryo-specific promoter ZM-leg1A, and the transgene was transferred to three generations by backcrossing with commercial inbred Zheng58. Its exogenous integration into the maize embryonic genome and tissue specific expression in seeds were confirmed by PCR and Southern blot and Western blot analysis, respectively. Transgenic plants at BC3 generation showed agronomic traits statistically similar to Zheng58 except for less plant height (154.0 cm vs 158.3 cm). The expression level of MAN5AS reached up to 26,860 units per kilogram of maize seeds. Compared with its counterpart produced in Pichia pastoris, seed-derived MAN5AS had higher temperature optimum (90°C), and remained more β-mannanase activities after pelleting at 80°C, 100°C or 120°C.
  
  
  CONCLUSIONS
  This study shows the genetically stable overexpression of a fungal β-mannanase in maize and offers an effective and economic approach for transgene containment in maize for direct utilization without any purification or supplementation procedures.
authors: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors: Xiaolu
authors: X
authors: Xu
authors: Yuhong
authors: Y
authors: Zhang
authors: Qingchang
authors: Q
authors: Meng
authors: Kun
authors: K
authors: Meng
authors: Wei
authors: W
authors: Zhang
authors: Xiaojin
authors: X
authors: Zhou
authors: Huiying
authors: H
authors: Luo
authors: Rumei
authors: R
authors: Chen
authors: Peilong
authors: P
authors: Yang
authors: Bin
authors: B
authors: Yao
mesh_terms: D000821:Animal Feed; D001203:Ascomycota / Q000201:enzymology* / Q000235:genetics*; D004789:Enzyme Activation; D004795:Enzyme Stability; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics; D010641:Phenotype; D010843:Pichia / Q000235:genetics; D012038:Regeneration; D012639:Seeds / Q000235:genetics* / Q000502:physiology; D014170:Transformation, Genetic; D003313:Zea mays / Q000235:genetics* / Q000502:physiology; D044902:beta-Mannosidase / Q000235:genetics* / Q000378:metabolism*
chemical_list: D044902:beta-Mannosidase