Allelopathic effects of Epichloë fungal endophytes: experiment and meta-analysis

Host-specific Epichloë spp. endophytic fungal symbionts of pooid grasses that produce herbivore-deterring alkaloids and alter the grass host's metabolite and protein profiles. Early observations suggested that Epichloë may have negative allelopathic effects on neighbouring plant species, particularly Trifolium spp. clovers, but subsequent allelopathy tests produced variable results. We examined two hypotheses: (1) Epichloë strains differ in allelopathic effect, and (2) Epichloë allelopathy negatively affects other plant species. We performed a greenhouse experiment using root exudates from Lolium perenne L. hosting different E. festucae var. lolii (Latch, M.J. Chr. & Samuels) C.W. Bacon & Schardl strains to compare their allelopathic effects on native legumes and forbs. We then used meta-analysis to examine the evidence to date for allelopathic effects of Epichloë endophytes. We found little difference in effect among E. festucae var. lolii strains and very little evidence for negative allelopathic effects of Epichloë in cool-season grasses across a range of methodologies, target plant species, and response measures. Negative allelopathic effects were detected only for root hair measures, which were from a single study. Positive effects on biomass were found for some experimental subgroups, including legumes. However, the majority of response variables showed no evidence for Epichloë allelopathy. Although there is currently little evidence for negative Epichloë allelopathic effects, our meta-analysis identified several research gaps. Experiments testing the functional belowground effects of Epichloë presence may help to determine its effects on non-host plant performance via plant-soil feedbacks.

Download Full-text

Propagation and Possible Allelopathic Effects of Vernoniazeylanica on Selected Bioassay Species

CORD ◽

10.37833/cord.v36i.428 ◽

2020 ◽

Vol 36 ◽

pp. 41-46

Author(s):

S.H.S. Senarathne ◽

S. S. Udumann

Keyword(s):

Seed Germination ◽

Plant Species ◽

Seedling Growth ◽

Contaminated Soil ◽

Leaf Extract ◽

Cocos Nucifera ◽

Test Plant ◽

Allelopathic Effect ◽

Aqueous Leaf Extract ◽

Allelopathic Effects

Vernonia zeylanica (L.) belongs to the family Asteraceae, is one of the major endemic weed species present in coconut (Cocos nucifera L.) plantations of the tropics, which propagates very easily. There is a possibility that this plant could also possess allelopathic effects, but this has not been scientifically tested. Thus, a study was carried out to determine the seed germination of V. zeylanica under soil moisture stress conditions, shoot propagation methods and possible allopathic effects of this species, on selected species in bioassay tests. Germination of V. zeylanica seeds was not observed at higher osmotic potential (-0.9 MPa). The highest sprouting percentage of this species were obtained with soft wood cuttings. The aqueous leaf extract was highly phytotoxic, and it significantly reduced germination and seedling growth of all bioassay species tested. Full strength (33.3 g L-1) aqueous extracts of leaves significantly reduced the germination percentage, root and hypocotyl growth rates of all species tested. The inhibitory effects were often dependent on concentration. However, the degree of inhibition varied among the test plant species. The seedling emergences of all four tested plants were severally inhibited when planted in V. zeylanica contaminated soil. The results indicated that incorporated aqueous leaf extract of V. zeylanica and its rhizosphere contaminated soil can suppress seed germination, seedling growth and seedling emergence of certain plant species indicating a possible allelopathic effect.

Download Full-text

Plant–soil feedbacks of exotic plant species across life forms: a meta-analysis

Biological Invasions ◽

10.1007/s10530-014-0685-2 ◽

2014 ◽

Vol 16 (12) ◽

pp. 2551-2561 ◽

Cited By ~ 42

Author(s):

Annelein Meisner ◽

W. H. Gera Hol ◽

Wietse de Boer ◽

Jennifer Adams Krumins ◽

David A. Wardle ◽

...

Keyword(s):

Plant Species ◽

Meta Analysis ◽

Life Forms ◽

Exotic Plant ◽

Exotic Plant Species ◽

Plant Soil

Download Full-text

Drought alters plant‐soil feedback effects on biomass allocation but not on plant performance

Plant and Soil ◽

10.1007/s11104-021-04861-9 ◽

2021 ◽

Author(s):

Rutger A. Wilschut ◽

Mark van Kleunen

Keyword(s):

Soil Moisture ◽

Plant Species ◽

Biomass Allocation ◽

Plant Performance ◽

Control Soil ◽

Feedback Effects ◽

Plant Soil ◽

Soil Feedback ◽

Species Specific ◽

Relative Root

Abstract Aims Drought events can alter the composition of plant and soil communities, and are becoming increasingly common and severe due to climate change. However, how droughts affect plant-soil feedbacks is still poorly understood. Plants accumulate species-specific rhizosphere communities, and droughts may have varying impacts across plant species and soil biota. We therefore tested the hypothesis that drought alters plant-soil feedbacks differently among closely related plant species that differ in their preferences for soil moisture. Methods In a two-phase greenhouse experiment, we first conditioned grassland soil with seven Geranium species and, as controls, we conditioned soil with a grass species or left soil unplanted. In the second phase, we grew the Geranium species in conspecific, grass-conditioned and unplanted soil, maintained soil moisture at 5 %, 10 % or 20 % (w/w), and determined biomass responses after 35 days. Results Independent of conditioning, plants showed a weaker performance with decreasing soil moisture. Under the driest conditions, soil conditioning by conspecifics most negatively affected relative root weight in comparison to plants growing in unplanted control soil, while the effects of conspecific conditioning on relative root weights were species-specific when compared to plants grown in grass-conditioned control soil. Conclusions We conclude that decreased soil moisture modified plant-soil feedback effects on biomass allocation, and that these modifications acted in species-specific ways. However, drought effects on plant-soil feedbacks were subtle, and did not affect overall plant performance. Therefore, plant-soil feedback effects on plant performance during a drought event may be limited in comparison with the direct effects of drought.

Download Full-text

Frugivore gut passage increases seed germination: an updated meta-analysis

10.1101/2021.10.12.462022 ◽

2021 ◽

Author(s):

Haldre S Rogers ◽

Brittany R Cavazos ◽

Ann Marie Gawel ◽

Alex T Karnish ◽

Courtenay A Ray ◽

...

Keyword(s):

Seed Germination ◽

Plant Communities ◽

Meta Analysis ◽

Ecological Impacts ◽

Plant Performance ◽

Positive Effects ◽

Gut Passage ◽

Multiple Predictor ◽

Meta Analyses ◽

Pulp Removal

Many plants rely on animal mutualists for reproduction. Quantifying how animal mutualists impact plant performance provides a foundation for modelling how change in animal communities affects the composition and functioning of plant communities. We performed a meta-analysis of 2539 experiments, 6 times more than the last comprehensive meta-analysis, examining how gut passage by frugivores influences seed germination. We simultaneously analyzed multiple predictor variables related to study methodology, location, and frugivore identity to disentangle methodological from ecological impacts on effect sizes. We found that gut passage by birds, fish, reptiles, bats, primates, and other mammals on average increased seed germination, but that the magnitude varied across vertebrate groups. The positive effects of gut passage were largely explained by the de-inhibitory effects of pulp removal rather than by the scarification of seed tissues. Some previous studies and meta-analyses that found no effect of gut passage only tested scarification or did not distinguish between these tests of scarification and pulp removal. We found that, for a typical fleshy-fruited plant species, the lack of gut passage reduces germination by 60%. From an evolutionary perspective, this indicates a large risk associated with reliance on animal mutualists that is balanced against the benefits of animal-mediated seed dispersal. From a conservation perspective, this highlights the potential for large demographic consequences of frugivore declines on plant populations. Our database and findings advance quantitative predictions for the role of fruit-frugivore interactions in shaping plant communities in the Anthropocene.

Download Full-text

Overexpression of MYB Genes and Increased Abiotic Stress Tolerance: A Meta-Analysis.

10.21203/rs.3.rs-23122/v1 ◽

2020 ◽

Author(s):

Yuanchun Ma ◽

Zhaolan Han ◽

Xiaowen Shang ◽

Lingxia Shao ◽

Ya Wang ◽

...

Keyword(s):

Salt Stress ◽

Abiotic Stress ◽

Stress Tolerance ◽

Plant Species ◽

Stress Responses ◽

Abiotic Stress Tolerance ◽

Meta Analysis ◽

Plant Performance ◽

Published Data ◽

Donor Type

Abstract Background: The MYB family of proteins is a large group of transcription factors found in all eukaryotes studied to date that has expanded significantly in plants where they are involved in a wide diversity of processes from development to abiotic stress responses. The overexpression of various MYB genes has been reported to improve stress tolerance in different plant species. However, due to the variety of plant species studied and the types of gene donors/recipients, along with different experimental conditions, it is difficult to interpret the roles of MYB genes in abiotic stress tolerance from published data.Result: We investigated the plant characteristics involved in cold, drought, and salt stress in MYB-overexpressing plants through the meta-analysis approach, and analyzed the degrees of influence on plant performance by experimental variables. The results show that two of the four measured plant parameters in cold-stressed plants, two of the six in drought-stressed, and four of the 13 in salt-stressed were significantly impacted by MYB overexpression by 22% or more. By contrast, only two of the 13 plant parameters were significantly impacted in non-stressed plants by 18% or more. Conclusions: These data suggest that the treatment medium, donor/recipient species, and donor type significantly influence the effects of MYB overexpression on drought stress tolerance. Under salt stress, the donor/recipient species, donor type, and stress duration all significantly affected the extent of MYB-mediated salt stress tolerance. This study compiles and analyzes the data across studies to help us understand the complex interactions that dictate the efficacy of heterologous MYB expression designed for improved abiotic stress tolerance in plants.

Download Full-text

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

HortScience ◽

10.21273/hortsci13370-18 ◽

2018 ◽

Vol 53 (12) ◽

pp. 1791-1798 ◽

Cited By ~ 1

Author(s):

Kevin M. Heinz ◽

Polly A. Harding ◽

Maria Julissa Ek-Ramos ◽

Heather Hernandez ◽

Peter C. Krauter ◽

...

Keyword(s):

Plant Growth ◽

Fungal Endophytes ◽

Plant Performance ◽

Plant Responses ◽

Natural Occurrence ◽

Aesthetic Quality ◽

Knock Out ◽

Positive Effects ◽

Fungal Entomopathogens ◽

The Impact

Endophytic fungi are increasingly studied for their ability to enhance plant performance in field crops, yet there are few equivalent studies in floricultural crops. Given the economic importance of these crops and pressures faced by growers to produce plants of high aesthetic quality, we surveyed the natural occurrence of foliar fungal endophytes in Knock Out® roses to identify candidate beneficial isolates. We also tested the effects of entomopathogenic fungal inocula on marigold and zinnia plant growth using different application approaches. Our survey of Knock Out® rose foliage collected from five sites within central Texas revealed at least 24 different fungal genera and 30 probable species, including some isolates providing plant stress tolerance and pathogens or antagonists of insects and nematode pests. The effects of entomopathogen inocula on plant growth varied with host plant (marigold vs. zinnia) and inoculation method (soil drench vs. seed soak). Plant responses were complex, but inoculation with Isaria fumosorosea Wize tended to have a negative effect on plant performance characteristics whereas Beauveria bassiana (Bals.-Criv.) Vuill. tended to have positive effects. When applied to marigold as a seedcoating, I. fumosorosea reduced germination, seedling fresh weight, and produced seedlings with a less compact form. By contrast, seeds inoculated with B. bassiana required less time to germinate, had higher germination rates, and increased the plant compactness. These results show that the impact of fungal entomopathogens applied as endophytes depends on the specific fungi-plant combination being examined. The effect of plant inoculation with entomopathogenic fungi within a pest management context requires further evaluation.

Download Full-text

Artemisia halodendron litters have strong negative allelopathic effects on earlier successional plants during vegetation restoration in a semi-arid sandy dune region in China

10.5194/egusphere-egu2020-6041 ◽

2020 ◽

Author(s):

Zhong Du ◽

Yongqing Luo ◽

Zhiqiang Yan ◽

Xueyong Zhao ◽

Yuqiang Li ◽

...

Keyword(s):

Seed Germination ◽

Plant Species ◽

Soil Seed Bank ◽

Vegetation Restoration ◽

Allelopathic Effect ◽

Successional Species ◽

Artemisia Halodendron ◽

Allelopathic Effects ◽

Arid Grasslands ◽

Semi Arid

Artemisia halodendron Turcz. ex Besser occurs following the appearance of a pioneer species, Agriophyllum squarrosum (L.) Moq., and the former &#8220;killed&#8221; and replaced the latter during the naturally vegetation succession in sandy dune regions in China. A previous study revealed that the foliage litter of A. halodendron had strong negative allelopathic effects on germination of the soil seed bank and on the seedling growth. It is unclear whether an allelopathic effect of A. halodendron litters positively or negatively affects the seed germination, leading to a progressively replacement of the plant species in sandy dune regions.We, therefore, carried out a seed germination experiment to determine the allelopathic effects of three litter types of A. halodendron (roots, foliage, and stems) on seed germination of six plant species that progressively occur along a successional gradient in the semi-arid grasslands of northeastern China.In line with our expectation, we found that the early-successional species rather than the late-successional species were negatively affected by the allelopathic effects of A. halodendron, and that the allelopathic effects on seed germination increase with increasing concentration of litter extracts, irrespective of litter types.Our study evidenced the negative allelopathic effects of A. halodendron on the species replacement and on the community composition during dune stabilization. Further studies are needed to better understand the successional process and thus to promote the vegetation restoration, as A. halodendron itself disappeared also during the process.

Download Full-text

Plant–soil feedbacks between arbuscular- and ecto-mycorrhizal communities

10.1101/228387 ◽

2017 ◽

Cited By ~ 2

Author(s):

Kohmei Kadowaki ◽

Satoshi Yamamoto ◽

Hirotoshi Sato ◽

Akifumi S. Tanabe ◽

Amane Hidaka ◽

...

Keyword(s):

Plant Species ◽

Plant Communities ◽

Growth Rates ◽

Community Assembly ◽

Mycorrhizal Plant ◽

Positive Effects ◽

Plant Soil ◽

Adult Trees ◽

Species Specific ◽

Seedling Community

AbstractSoil microbiomes of adult trees exert species-specific effects on the survival and growth of seedlings1-6, yet empirical evidence that such plant–soil microbiome interaction drives seedling community assembly remains scarce. Here we show that mycorrhizal fungal communities determine seedling community assembly by controlling how resident plant communities alter the growth of newly established seedlings. We reciprocally introduced seedling communities of arbuscular-and ecto-mycorrhizal plant species to replicated mesocosms to follow the effects of mycorrhizal type match/mismatch with resident plant communities on seedling growth rates. The growth rates of recruited seedlings were generally higher under resident trees of the same mycorrhizal types than under those of different mycorrhizal types, generating positive plant–soil feedbacks through mycorrhizal-type matching. Such positive effects of matching were linked with seedlings’ greater acquisition rates of mycorrhizal symbionts from matched resident plants than from mismatched plants, and such linkage was pronounced for ecto-mycorrhizal plant species. In contrast, under the condition of mycorrhizal-type matching between resident plants and seedlings (i.e., within-mycorrhizal-type comparison), plant–soil feedback effects varied considerably in their sign and strength among resident–seedling species combinations. Consequently, the assembly of a temperate tree seedling community is driven by a combination of species-specific plant–soil feedbacks and the match/mismatch of mycorrhizal type between resident plants and seedlings.

Download Full-text