title: Plant-plant-microbe mechanisms involved in soil-borne disease suppression on a maize and pepper intercropping system.
abstract: BACKGROUND
  Intercropping systems could increase crop diversity and avoid vulnerability to biotic stresses. Most studies have shown that intercropping can provide relief to crops against wind-dispersed pathogens. However, there was limited data on how the practice of intercropping help crops against soil-borne Phytophthora disease.
  
  
  RESULTS
  Compared to pepper monoculture, a large scale intercropping study of maize grown between pepper rows reduced disease levels of the soil-borne pepper Phytophthora blight. These reduced disease levels of Phytophthora in the intercropping system were correlated with the ability of maize plants to form a "root wall" that restricted the movement of Phytophthora capsici across rows. Experimentally, it was found that maize roots attracted the zoospores of P. capsici and then inhibited their growth. When maize plants were grown in close proximity to each other, the roots produced and secreted larger quantities of 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and 6-methoxy-2-benzoxazolinone (MBOA). Furthermore, MBOA, benzothiazole (BZO), and 2-(methylthio)-benzothiazole (MBZO) were identified in root exudates of maize and showed antimicrobial activity against P. capsici.
  
  
  CONCLUSIONS
  Maize could form a "root wall" to restrict the spread of P. capsici across rows in maize and pepper intercropping systems. Antimicrobe compounds secreted by maize root were one of the factors that resulted in the inhibition of P. capsici. These results provide new insights into plant-plant-microbe mechanisms involved in intercropping systems.
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Qi
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Xinyue
authors.initials: X
authors.lastname: Mei
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Liao
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Xupo
authors.initials: X
authors.lastname: Ding
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Deng
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Fan
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Xiahong
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Horticulture and Landscape Architecture and Center for Rhizosphere Biology, Colorado State University, Fort Collins, Colorado 80523, United States of America.
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Vivanco
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Chengyun
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Youyong
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, China.
authors.forename: Shusheng
authors.initials: S
authors.lastname: Zhu
mesh_terms: D000383:Agriculture / Q000379:methods*; D004780:Environment, Controlled; D006790:Host-Parasite Interactions; D010838:Phytophthora / Q000187:drug effects / Q000502:physiology; D031701:Piper / Q000254:growth & development* / Q000382:microbiology / Q000469:parasitology*; D010935:Plant Diseases / Q000382:microbiology / Q000469:parasitology* / Q000517:prevention & control*; D010936:Plant Extracts / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry / Q000382:microbiology / Q000469:parasitology; D058441:Rhizosphere; D012987:Soil / Q000469:parasitology*; D012988:Soil Microbiology; D003313:Zea mays / Q000737:chemistry / Q000254:growth & development*
chemical_list: D010936:Plant Extracts; D012987:Soil