Infection of Commercial Hybrid Primula Seed by Botrytis cinerea and Latent Disease Spread Through the Plants

Abstract

Botrytis cinerea occurred commonly on cultivated Primula xpolyantha seed. The fungus was mostly on the outside of the seed but sometimes was present within the seed. The fungus frequently caused disease at maturity in plants grown from the seed, demonstrated by growing plants in a filtered airflow, isolated from other possible sources of infection. Young, commercially produced P. xpolyantha plants frequently had symptomless B. cinerea infections spread throughout the plants for up to 3 months, with symptoms appearing only at flowering. Single genetic individuals of B. cinerea, as determined by DNA fingerprinting, often were dispersed widely throughout an apparently healthy plant. Plants could, however, contain more than one isolate.

Persistent, symptomless, systemic, and seed-borne infection of lettuce by Botrytis cinerea

“…To summarise, this study has established that both seed-borne and airborne infection of lettuce seedlings with B. cinerea give rise to long-lived systemic endophyte-like infections in all parts of plants, similar to endophytic infections found in other asteracae by other fungi (Gange et al, 2007), and the B. cinerea infections previously found in Primulaxpolyantha ( Barnes and Shaw, 2003). Further work remains to be done particularly studies on vertical transmission of the fungus within the host; the frequency with which such infections occur in wild plants and other commercial crops; and the functional implications of these overlooked infections.…”

“…x polyantha (Barnes and Shaw, 2003), but is somewhat at variance with detailed studies of the infection cycle of the pathogen in other hosts. Short phases of endophytic growth by Botrytis within undamaged plant tissues have been reported in strawberry (Bristow et al, 1986), blackcurrant (McNicol andWilliamson, 1989) and raspberry (Williamson et al, 1987), but these were localised and in raspberry, blackcurrant and grape followed entry through flower parts.…”

“…Lettuce is the second host in which this systemic, symptomless progression has been demonstrated, alongside commercial hybrid Primula ( Barnes and Shaw, 2003). While this type of growth is known in many non-pathogenic fungi and pathogens-including for example Leptosphaeria Fig.…”

“…In grape, kiwi, strawberry and other hosts, it may infect to form a small infection which then becomes quiescent and is activated by the onset of senescence or stress of the host tissue (Bristow et al, 1986;Coertze and Holz, 2002;Keller et al, 2003;Michailides and Elmer 2000). However, Barnes and Shaw (2003) found that B. cinerea could grow systemically but without symptoms in cultivated Primula x polyantha, so that a single isolate could be present throughout an apparently healthy plant-an endophytic infection. These infections arose from airborne spores but appeared also to be seed-borne, commonly externally but sometimes also within seed.…”

A Novel Botrytis Species Is Associated with a Newly Emergent Foliar Disease in Cultivated Hemerocallis

“…There is also considerable evidence that the commensal endophytic state and a parasitic, pathogenic state can be highly plastic [2], [4]. Indeed, there is confirmation that several fungal diseases of plants can exist as a symptomless, endophytic infection – as, for instance, in the necrotrophic generalist Botrytis cinerea (grey mould) [5],[6] and obligate biotrophic Albugo species [7]. Anthropogenic change to natural environments is also likely to be a major factor in promoting the emergence of new pathogens [1].…”