Arabica-like flavour in a heat-tolerant wild coffee species

Wild coffee species are critical for coffee crop development and, thus, for sustainability of global coffee production. Despite this fact, the extinction risk and conservation priority status of the world’s coffee species are poorly known. Applying IUCN Red List of Threatened Species criteria to all (124) wild coffee species, we undertook a gap analysis for germplasm collections and protected areas and devised a crop wild relative (CWR) priority system. We found that at least 60% of all coffee species are threatened with extinction, 45% are not held in any germplasm collection, and 28% are not known to occur in any protected area. Existing conservation measures, including those for key coffee CWRs, are inadequate. We propose that wild coffee species are extinction sensitive, especially in an era of accelerated climatic change.

Download Full-text

Endophytic fungi associated with four endemic wild coffee species (Mascarocoffea) in Madagascar

African Crop Science Journal ◽

10.4314/acsj.v29i4.3 ◽

1970 ◽

Vol 29 (4) ◽

pp. 459-470

Author(s):

A.J. Zananirina ◽

B.M. Iacomi ◽

D.A.D. Rakoto-Ranoromalala ◽

I. Ratsizafy ◽

A.T.E. Razakatiana ◽

...

Keyword(s):

Endophytic Fungi ◽

Neofusicoccum Parvum ◽

Trichoderma Sp ◽

Colletotrichum Siamense ◽

Alternaria Sp ◽

Fusarium Sp ◽

Coffee Plants ◽

Rhizopus Sp ◽

Wild Coffee ◽

Coffee Species

Mascarocoffea are wild coffee plants endemic to Madagascar. These plants produce diverse, often specific biomolecules that are not found in cultivated coffee plants. Production of these compounds could be due to interactions between the endophytes and the host plant. Few studies have been carried out on the richness and diversity of microorganisms associated with these coffee plants. The objective of this study was to identify endophytic fungi isolated from the leaves of species of Mascarocoffea by morphological and molecular methods. Fifteen taxa were morphologically identified among the 30 isolated. These included Phyllosticta sp., Colletotrichum sp., Daldinia sp., Diaporthe sp., Cladosporium sp., Fusarium sp.01, Fusarium sp. 02, Fusarium sp. 03, Monilinia sp., Trichoderma sp., Alternaria sp, Penicillium sp., Aspergillus niger, Rhizopus sp. and Nigrospora sp. The phylum Ascomycota was the most represented, with 14 taxa and 1 taxon (Rhizopus sp.) belonging to the phylum of Zygomycota. Molecular characterisation confirmed of the identity of these 15 taxa and those of the morphologically Unidentified (NI) mycotaxa including Colletotrichum karstii, Colletotrichum siamense, Neofusicoccum parvum, Colletotrichum siamense, Punctularia strigosozonata, Stemphylium solani, Phoma multirostrata, Calophoma complonata, Daldinia vanderguchtiae, Phoma exigua and Boremia exigua. This study allowed us to identify the endophytic fungi isolated from Mascarocoffea leaves from Madagascar.

Download Full-text

Exploring Morpho-Physiological Variation for Heat Stress Tolerance in Tomato

Plants ◽

10.3390/plants10020347 ◽

2021 ◽

Vol 10 (2) ◽

pp. 347

Author(s):

Samikshya Bhattarai ◽

Joshua Harvey ◽

Desire Djidonou ◽

Daniel Leskovar

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Open Field ◽

Electrolyte Leakage ◽

Leaf Gas Exchange ◽

Total Yield ◽

Stress Conditions ◽

Heat Injury ◽

Injury Index ◽

Heat Tolerant

Texas tomato production is vulnerable to extreme heat in the spring-summer cropping period, which is exacerbated by the lack of superior genetic materials that can perform well in such environments. There is a dire need for selecting superior varieties that can adapt to warm environments and exhibit high yield stability under heat stress conditions. This research aimed at identifying heat-tolerant varieties under heat-stress conditions in controlled and open-field environments and was carried out in three stages. For the first experiment, 43 varieties were screened based on yield responses in natural open-field environment. From those, 18 varieties were chosen and exposed to control (greenhouse: 26/20 °C) and constant heat-stress (growth-chamber: 34/24 °C) conditions for three months. Measurements were done for chlorophyll fluorescence, chlorophyll content (SPAD), plant height, stem diameter and heat injury index (HII). The last experiment was conducted in an open field with a pool of varieties selected from the first and second experiments. Leaf gas exchange, leaf temperature, chlorophyll fluorescence, SPAD value, electrolyte leakage, heat injury index and yield were assessed. From the combined studies, we concluded that heat-tolerant genotypes selected by using chlorophyll fluorescence and HII in controlled heat-stress conditions also exhibited heat-tolerance in open-field environments. Electrolyte leakage and HII best distinguished tomato varieties in open-field environments as plants with low electrolyte leakage and HII had higher total yield. 'Heat Master,' 'New Girl,' 'HM-1823,' 'Rally,' 'Valley Girl,' 'Celebrity,' and 'Tribeca' were identified as high heat-tolerant varieties. Through trait correlation analysis we provide a better understanding of which traits could be useful for screening and breeding other heat-tolerant tomato varieties.

Download Full-text

New species and records of Trichoderma isolated as mycoparasites and endophytes from cultivated and wild coffee in Africa

Scientific Reports ◽

10.1038/s41598-021-84111-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

María del Carmen H. Rodríguez ◽

Harry C. Evans ◽

Lucas M. de Abreu ◽

Davi M. de Macedo ◽

Miraine K. Ndacnou ◽

...

Keyword(s):

New Species ◽

Cloud Forest ◽

Elongation Factor ◽

Classical Biological Control ◽

Hemileia Vastatrix ◽

Translation Elongation ◽

Coffee Leaf Rust ◽

Novel Taxa ◽

Coffee Plants ◽

Wild Coffee

AbstractA survey for species of the genus Trichoderma occurring as endophytes of Coffea, and as mycoparasites of coffee rusts (Hemileia), was undertaken in Africa; concentrating on Cameroon and Ethiopia. Ninety-four isolates of Trichoderma were obtained during this study: 76 as endophytes of healthy leaves, stems and berries and, 18 directly from colonized rust pustules. A phylogenetic analysis of all isolates used a combination of three genes: translation elongation factor-1α (tef1), rpb2 and cal for selected isolates. GCPSR criteria were used for the recognition of species; supported by morphological and cultural characters. The results reveal a previously unrecorded diversity of Trichoderma species endophytic in both wild and cultivated Coffea, and mycoparasitic on Hemileia rusts. Sixteen species were delimited, including four novel taxa which are described herein: T. botryosum, T. caeruloviride, T. lentissimum and T. pseudopyramidale. Two of these new species, T. botryosum and T. pseudopyramidale, constituted over 60% of the total isolations, predominantly from wild C. arabica in Ethiopian cloud forest. In sharp contrast, not a single isolate of Trichoderma was obtained using the same isolation protocol during a survey of coffee in four Brazilian states, suggesting the existence of a ‘Trichoderma void’ in the endophyte mycobiota of coffee outside of Africa. The potential use of these African Trichoderma isolates in classical biological control, either as endophytic bodyguards—to protect coffee plants from Hemileia vastatrix, the fungus causing coffee leaf rust (CLR)—or to reduce its impact through mycoparasitism, is discussed, with reference to the on-going CLR crisis in Central America.

Download Full-text

Heat-tolerant hot pepper exhibits constant photosynthesis via increased transpiration rate, high proline content and fast recovery in heat stress condition

Scientific Reports ◽

10.1038/s41598-021-93697-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sherzod Nigmatullayevich Rajametov ◽

Eun Young Yang ◽

Myeong Cheoul Cho ◽

Soo Young Chae ◽

Hyo Bong Jeong ◽

...

Keyword(s):

Heat Treatment ◽

Heat Stress ◽

Heat Tolerance ◽

Transpiration Rate ◽

Stress Condition ◽

Proline Content ◽

Hot Pepper ◽

Fast Recovery ◽

Heat Stress Condition ◽

Heat Tolerant

AbstractUnderstanding the mechanism for heat tolerance is important for the hot pepper breeding program to develop heat-tolerant cultivars in changing climate. This study was conducted to investigate physiological and biochemical parameters related to heat tolerance and to determine leaf heat damage levels critical for selecting heat-tolerant genotypes. Seedlings of two commercial cultivars, heat-tolerant ‘NW Bigarim’ (NB) and susceptible ‘Chyung Yang’ (CY), were grown in 42 °C for ten days. Photosynthesis, electrolyte conductivity, proline content were measured among seedlings during heat treatment. Photosynthetic rate was significantly reduced in ‘CY’ but not in ‘NB’ seedlings in 42 °C. Stomatal conductivity and transpiration rate was significantly higher in ‘NB’ than ‘CY’. Proline content was also significantly higher in ‘NB’. After heat treatment, leaf heat damages were determined as 0, 25, 50 and 75% and plants with different leaf heat damages were moved to a glasshouse (30–32/22–24 °C in day/night). The growth and developmental parameters were investigated until 70 days. ‘NB’ was significantly affected by leaf heat damages only in fruit yield while ‘CY’ was in fruit set, number and yield. ‘NB’ showed fast recovery after heat stress compared to ‘CY’. These results suggest that constant photosynthetic rate via increased transpiration rate as well as high proline content in heat stress condition confer faster recovery from heat damage of heat-tolerant cultivars in seedlings stages.

Download Full-text