Healing of Gladioulus grandiflora corms and Fusarium oxysporum infection

Authors: CRUZ, RENATA - Universidade Federal De Vicosa; RIBEIRO, WELLINGTON - Federal University Of Campina Grande; SILVA, SILVANDA - Paraiba University; FINGER, FERNANDO - Universidade Federal De Vicosa; ZANUNCIO, JOSE - Universidade Federal De Vicosa; CORREA, ELIDA - Paraiba University; BRUNO, RISELANE - Paraiba University; Fugate, Karen; DA COSTA, FRANCISCLEUDO - Federal University Of Campina Grande; ARAUJO, RAILENE - Universidade Federal De Vicosa

Submitted to: Plant Signaling and Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2019
Publication Date: 8/14/2019
Citation: Cruz, R.R., Ribeiro, W.S., Silva, S.M., Finger, F.L., Zanuncio, J.C., Correa, E.B., Bruno, R.L., Fugate, K.K., Da Costa, F.B., Araujo, R.H. 2019. Healing of Gladioulus grandiflora corms and Fusarium oxysporum infection. Plant Signaling and Behavior. 1559-2324. https://doi.org/10.1080/15592324.2019.1652520.
DOI: https://doi.org/10.1080/15592324.2019.1652520

Interpretive Summary: Gladiolus corms are highly susceptible to storage rot caused by the fungal pathogen, Fusarium oxysporum. Injuries to corms that occur during the harvest and handling of corms facilitate infection by this pathogen, although healing of these injuries is expected to reduce storage losses to this disease organism. Wound-healing processes in gladiolus, however, are not well characterized and relationships between wound-healing and the ability of Fusarium to infect corms have not been previously examined. Therefore, physical and biochemical changes in corms in response to wounding were determined and the effect of these wound-healing processes on the ability of Fusarium to infect corms was determined. Injury resulted in cell collapse and cell death at the site of injury, and wounded corms declined in weight and respired at higher rates than uninjured corms. Within 3 days after injury, corms sealed off wound sites from the environment by producing and depositing suberin, lignin, and melanin, three water-impermeable polymers. The ability of Fusarium to infect gladiolus corms also declined three days after injury, likely due to the formation of these polymers and the sealing of the wound site.

Technical Abstract: Gladiolus grandiflorus L. is highly susceptible to Fusarium and losses caused by this disease varies from 60% to 100%. Injuries caused during harvest, transport and inadequate storage, facilitate infection. The dynamics of wound healing can reduce infection by Fusarium. The objective was to characterize the wound healing in corms of G. grandiflora stored under refrigeration and how it affects the entry and establishment of F. oxysporum f. sp. gladioli infection. Corms were wounded and stored at 12 ± 4°C and relative humidity of 90 ± 5%. Cell damage, fresh weight loss, respiration, phenolic compounds, tissue darkening, suberization, lignification and resistance to infection were evaluated. Wounds on corms caused transepidermal damage with collapse and cell death. Physiological (increased loss of mass and respiration) and biochemical changes (deposition of lignin and suberin, enzymatic activity) occurred in the cells neighboring those death by the injury. The injury caused gradual darkening of the tissue, injured and neighbor. Fusarium oxysporum infection decreased with wound healing. The healing of injured G. grandiflora corms stored at 12ºC occurs from the 3rd day after injury by the accumulation of suberin, lignin, and melanin, inhibiting F. oxysporum f. sp. gladioli infection.