The fungal endophyteChaetomium globosumnegatively affects both above- and belowground herbivores in cotton

Abstract

Mutualistic plant-endophyte symbioses can benefit plants by increasing host fitness through reductions in herbivory. The fungus, Chaetomium globosum strain TAMU 520, was previously isolated as an endophyte from cotton (Gossypium hirsutum) and can be re-inoculated to systemically colonize cotton plants via seed treatment. We evaluated the potential impacts of the endophyte in cotton on plant parasitic nematodes belowground, along with piercing-sucking and chewing insects aboveground. Endophytic C. globosum inhibited root-knot nematode (Meloidogyne incognita) infection and reduced female reproduction belowground. To confirm the endophytic effect of C. globosum on root-knot nematode, a contact fungicide was applied to remove soil-borne and epiphytic C. globosum Consistent inhibition of nematode activity was observed post-fungicide treatment, with positive C. globosum colonization confirmed within plant tissues. Aboveground, endophytic C. globosum also negatively affected the fecundity of both cotton aphids (Aphis gossypii) and beet armyworms (Spodoptera exigua). Faster development rates and smaller head capsule of beet armyworm larvae were observed when fed Chaetomium-colonized plants. However, no larval weight difference was found between Chaetomium-colonized and control plants. No consistent effect on plant performance was found across experiments. Our findings illustrate how a single facultative fungal endophyte can increase plant systemic resistance against a range of invertebrate herbivores in a major crop.

Tapping Into the Cotton Fungal Phytobiome for Novel Nematode Biological Control Tools

“…The use of beneficial fungi associated with plants that may confer increased resistance or tolerance to nematodes could provide an alternative to chemical applications for their control (Cabanillas et al 1988;Hallmann and Sikora 1996;Latch 1993;Martinez-Beringola et al 2013;Mendoza and Sikora 2009;Tian et al 2014;Waweru et al 2013). Certain beneficial strains of Fusarium spp., Pochonia chlamydosporia, Phialemonium inflatum, Piriformospora indica, and Chaetomium globosum, have been reported to have antagonistic effects on nematodes while being present in plants as endophytes (Bajaj et al 2015;Larriba et al 2015;Martinuz et al 2015;Yan et al 2011;Zhou et al 2016;Zhou et al 2018).…”

Fungal Endophytes in Knock Out® Rose and Performance Effects of Entomopathogens on Marigold and Zinnia

“…and Chaetomium cochliodes Palliser were collected from two survey sites. Zhou et al (2016) reported that C. glabosum strain TAMU 520 inhibited rootknot nematode (Meloidogyne incognita (Kofold & White) Chitwood) infection and reduced female reproduction on cotton roots. Aboveground, endophytic C. globosum reduced the fecundity of both cotton aphid, Aphis gossypii Glover, and beet armyworm, Spodoptera exigua (H€ ubner).…”

Endophytic fungi alter sucking bug responses to cotton reproductive structures

“…We also detected occasional colonization of untreated control plants by the target endophytes, but do not know if these rare events were due to contamination prior to planting or naturally occurring colonization during subsequent plant growth. Overall, our colonization and insect behavioral findings are consistent with previous studies using these same isolates that have demonstrated endophytic colonization of cotton along with associated treatment effects on cotton aphid ( Aphis gossypium ), cotton bollworm ( Helicoverpa zea ) and root‐knot nematode ( Meloidogyne incognita ) performance and reproduction, as well as plant growth (Lopez et al ., ; Lopez & Sword, ; Zhou et al ., ,b).…”

“…Although largely ignored until recently (Porras‐Alfaro & Bayman, ; Wani et al ., ), a growing number of studies demonstrate that the presence of these facultative endophytes in the plant can be manipulated in both mono‐ and dicots through the targeted inoculation of candidate fungi. These endophyte‐colonized plants can negatively affect the performance and survival of a range of both above‐ and below‐ground herbivores (e.g., Gurulingappa et al ., ; Hernawati et al ., ; Akello & Sikora, ; Menjivar et al ., ; Gange et al ., ; Martinuz et al ., ; Thakur et al ., ; Akutse et al ., ; Batta, ; Lopez et al ., ; Lopez & Sword, ; Zhou et al ., ,b). Facultative fungal endophytes can also be involved in nutrient transfer to plants, and positively affect plant growth, thereby potentially serving as multifaceted tools for plant protection and health in agricultural systems (Behie et al ., ; Behie & Bidochka, ; Barelli et al ., ; Jaber & Enkerli, ; Lugtenberg et al ., ).…”

“…Facultative fungal endophytes have been shown to affect the feeding behavior and performance of a wide range of insect herbivores from different feeding guilds with varying effects (Hartley & Gange, ; Gange et al ., ) including phloem‐feeders such as aphids and whiteflies (Hernawati et al ., ; Akello & Sikora, ; Menjivar et al ., ; Lopez et al ., ; Zhou et al ., ,b), dipterans (Akutse et al ., ), beetles (Newcombe et al ., ; Biswas et al ., ), caterpillars (Bing & Lewis, ; Lopez & Sword, ; Thakur et al ., ; Batta, ; Zhou et al ., ,b), grasshoppers (Gurulingappa et al ., ), and hymenopteran gall wasps (Quesada‐Moraga et al ., ). Notably missing from these examples are negative effects of facultative fungal endophytes on the true bugs (Hemiptera: suborder Heteroptera).…”