Tag Archives: #breeding

Discovery of Flowering Gene in Cacao May Lead To Accelerated Breeding Strategies (Agriculture)

For the first time, Penn State researchers have identified a gene that controls flowering in cacao, a discovery that may help accelerate breeding efforts aimed at improving the disease-ridden plant, they suggested.

Characterizing the Flowering Locus T gene in cacao, responsible for the production of florigen — a protein that triggers flowering in most plants — is important, according to study co-author Mark Guiltinan, J. Franklin Styer Professor of Horticultural Botany and professor of plant molecular biology. He expects this advancement to enable scientists to develop disease-resistant trees faster, which is critical because 20% to 30% of the world’s cacao crop is lost to disease annually.

“Breeding tree crops like cacao is very slow and can take 20 or more years to release a new variety,” he said. “Knowledge of the mechanisms of flowering may lead to methods to accelerate cacao breeding and to develop trees that produce fruit sooner than conventional varieties, which takes two to four years. Each year we move closer to these goals as we continue to explore the molecular biology of the cacao tree.”

To find the flowering gene in cacao, lead researcher Sarah Prewitt, doctoral candidate in plant science in the College of Agricultural Sciences, first looked at genes known to be responsible for flowering in the Arabidopsis plant, the genome of which has been studied widely for decades. Before finding the cacao flowering gene, she tested an Arabidopsis flowering gene in cacao to see how the plant developed.

Testing her theory, she overexpressed that gene to trigger very early flowering in cacao “plantlets” in the lab and showed that those tiny flowers produced grains of pollen that were viable.

“To find the flowering gene in cacao, we used a bioinformatics approach, taking the sequence of the gene from Arabidopsis and looking for similar genes in the cacao genome,” Prewitt said. “I found the cacao gene that promotes flowering because the sequences look very similar.”

The fungal disease black pod rot, shown here in cacao seed pods, is a serious problem in all areas of the world where the crop is grown. Caused by the fungus Phytophthora, black pod rot causes pod losses of up to 30% and kills as many as 10% of the trees annually. Researchers hope to breed disease-resistant trees, and finding the cacao flowering gene promises to speed up their efforts. © PlantVillage, Penn State

Geneticists consider the function of the florigen flowering gene to be “highly conserved,” Prewitt added. “That means the gene is extremely consistent — it does what it does in every plant genome that you look in,” she said. “The florigen flowering gene certainly has been looked at in a lot of plants, and it’s very reliable. It controls the timing of flowering.”

In findings published May 15 in BMC Plant Biology, the researchers reported on the role of cacao’s single flowering gene, Flowering Locus T, demonstrated by gene-expression analysis. They also documented the results of their introduction of the flowering gene from Arabidopsis into cacao. Overexpressing that gene resulted in “precocious” flowering in cacao tissue culture, they explained, which demonstrated the extremely similar function of florigen genes and the mechanisms that control flowering in both Arabidopsis and cacao.

While intriguing on a scientific level, the discovery of the cacao Flowering Locus T gene could have a potentially significant, real-world impact, Guiltinan noted, by helping to improve the lives of millions of cacao farmers in developing countries sooner than previously thought possible. He pointed out that the breeding of cacao varieties with high yields, disease resistance, resilience to climate change and desirable quality traits is an important component of a broader goal to develop sustainable farming systems for cacao.

“Better cacao varieties can increase the income, and thus the well-being, of cacao farmers who live in some of the most impoverished regions of the world, such as West Africa,” he said. “In turn, this will benefit the economies of these countries and the environment and will provide a sustainable source of the main raw ingredient for the chocolate industry.”

Also involved in the research were Siela Maximova, research professor of plant biotechnology, and Akiva Shalit-Kaneh, postdoctoral scholar in plant science.

Penn State’s College of Agricultural Sciences, the Huck Institutes of the Life Sciences, the Penn State Endowed Program in the Molecular Biology of Cacao and the U.S. Department of Agriculture’s National Institute of Food and Agriculture supported this work.

Featured image: In the research, embryonic cacao, over expressing the florigen gene, develop tiny flowers in tissue culture. This study is significant because cacao trees typically don’t flower until they are between three and eight years of age. Such early flowering promises to greatly speed up breeding to develop disease-resistant trees. © Sarah Prewitt, Penn State


Reference: Prewitt, S.F., Shalit-Kaneh, A., Maximova, S.N. et al. Inter-species functional compatibility of the Theobroma cacao and Arabidopsis FT orthologs: 90 million years of functional conservation of meristem identity genes. BMC Plant Biol 21, 218 (2021). https://doi.org/10.1186/s12870-021-02982-y


Provided by Penn State

All-purpose Dinosaur Opening Reconstructed for the First Time (Paleontology)

For the first time ever, a team of scientists, led by the University of Bristol, have described in detail a dinosaur’s cloacal or vent – the all-purpose opening used for defecation, urination and breeding.

A reconstruction of Psittacosaurus illustrating how the cloacal vent may have been used for signalling during courtship. © Bob Nicholls/Paleocreations.com 2020

Although most mammals may have different openings for these functions, most vertebrate animals possess a cloaca. 

Although we know now much about dinosaurs and their appearance as feathered, scaly and horned creatures and even which colours they sported, we have not known anything about how the vent appears.

Dr Jakob Vinther from the University of Bristol’s School of Earth Sciences, along with colleagues Robert Nicholls, a palaeoartist, and Dr Diane Kelly, an expert on vertebrate penises and copulatory systems from the University of Massachusetts Amherst, have now described the first cloacal vent region from a small Labrador-sized dinosaur called Psittacosaurus, comparing it to vents across modern vertebrate animals living on land.

Dr Vinther said: “I noticed the cloaca several years ago after we had reconstructed the colour patterns of this dinosaur using a remarkable fossil on display at the Senckenberg Museum in Germany which clearly preserves its skin and colour patterns.

Close up of the preserved cloacal vent in Psittacosaurus and the authors’ reconstruction of it. © Kelly et al.

“It took a long while before we got around to finish it off because no one has ever cared about comparing the exterior of cloacal openings of living animals, so it was largely unchartered territory.”

Dr Kelly added: “Indeed, they are pretty non-descript. We found the vent does look different in many different groups of tetrapods, but in most cases it doesn’t tell you much about an animal’s sex.

“Those distinguishing features are tucked inside the cloaca, and unfortunately, they’re not preserved in this fossil.”

The cloaca is unique in its appearance but exhibits features reminiscent to living crocodylians such as alligators and crocodiles, which are the closest living relatives to dinosaurs and other birds.

The researchers note that the outer margins of the cloaca are highly pigmented with melanin. They argue that this pigmentation provided the vent with a function in display and signalling, similar to living baboons and some breeding salamanders.

Psittacosaurus specimen from Senckenberg museum of Natural History, preserving skin and pigmentation patterns and the first, and only known, cloacal vent. © Jakob Vinther, University of Bristol and Bob Nicholls/Paleocreations.com 2020

The authors also speculate that the large, pigmented lobes on either side of the opening could have harboured musky scent glands, as seen in living crocodylians.

Birds are one the few vertebrate groups that occasionally exhibit visual signalling with the cloaca, which the scientists now can extend back to the Mesozoic dinosaur ancestors.

Robert Nicholls said: “As a palaeoartist, it has been absolutely amazing to have an opportunity to reconstruct one of the last remaining features we didn’t know anything about in dinosaurs.

“Knowing that at least some dinosaurs were signalling to each other gives palaeoartists exciting freedom to speculate on a whole variety of now plausible interactions during dinosaur courtship. It is a game changer!”

Reference: ‘A cloacal opening in a non-avian dinosaur’ by J. Vinther, R. Nicholls and D. Kelly in Current Biology, 2021. https://www.cell.com/current-biology/fulltext/S0960-9822(20)31891-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982220318911%3Fshowall%3Dtrue

Provided by University of Bristol

Ringo Starr Of The Bird World Heading for Extinction (Ornithology / Biology)

New research from The Australian National University (ANU) shows palm cockatoos, renowned for their human-like musical drumming behaviour, are threatened with extinction.

According to co-author Professor Rob Heinsohn, the “animal kingdom’s match for Ringo Starr or Phil Collins” is facing rapidly declining population numbers.

“These shy and elusive birds, iconic to Cape York Peninsula in Far North Queensland, fashion thick drum sticks from branches, grip them with their feet and bang them rhythmically on the tree trunk, all the while displaying to females,” Professor Heinsohn said.

“Sadly, palm cockatoos have one of the slowest breeding rates of any bird, and our study shows the population is not producing enough young to replace the birds that die.”

The research used data from a long-term monitoring project together with new genetic information to work out how connected the scattered birds are on Cape York, and how well the good breeders compensate for those that fail to reproduce.

“Even best case scenarios show that the overall population will go down by more than a half in 49 years, the equivalent of three generations for the birds,” lead author Dr Miles Keighley said.

“This fast rate of decline means that the palm cockatoos qualify as ‘endangered’ under International Union for Conservation of Nature criteria.”

ANU researchers will work closely with the Queensland government to change the official conservation status of palm cockatoos.

“Long-lived birds like palm cockatoos, especially those that live in remote areas, are incredibly hard to study,” Professor Heinsohn said.

“We have worked very hard for over 20 years to understand the population trends. We used computer simulation techniques that allow us to look into the future – it’s a bit like having a crystal ball. But it only works if you have good data that tells you how the birds are tracking here and now.

“Palm cockatoos are very special birds. No other animal apart from humans fashions its own musical instrument, let alone creates its own rhythm.

“This only occurs among the palm cockatoos of Cape York Peninsula, adding extra impetus for protecting them and reversing the worrying downward trend.”

The research has been published in Biological Conservation.

References: Miles V. Keighley, Stephen Haslett, Christina N. Zdenek, Robert Heinsohn, “Slow breeding rates and low population connectivity indicate Australian palm cockatoos are in severe decline”, Biological Conservation, Volume 253, 2021, 108865, ISSN 0006-3207,
https://doi.org/10.1016/j.biocon.2020.108865.
http://www.sciencedirect.com/science/article/pii/S000632072030923X

Provided by Australian National University (ANU)

Plovers More Likely To Divorce After Successful Breeding (Biology)

When individuals breed more than once, parents are faced with the choice of whether to re-mate with their old partner or divorce and select a new mate. Evolutionary theory predicts that, following successful reproduction with a given partner, that partner should be retained for future reproduction. However, recent work in a polygamous bird also called shorebird / plover, has instead indicated that successful parents divorced more often than failed breeders, because one parent can benefit by mating with a new partner and reproducing shortly after divorce.

The researchers investigated whether successful breeding predicts divorce using data from 14 well-monitored populations of Charadrius plovers in the world.

These shorebirds tend to lay two to four eggs per nest and can have up to four breeding attempts per season.

Plover chicks mature quickly and fly the nest around a month after hatching; in most plover species both parents care for the hatchlings, but in some species either parent can desert the nest to breed again with a new mate.

Surprisingly, the researchers found that pairs that successfully raised chicks were more likely to divorce, whereas unsuccessful pairs tended to stick together and try breeding again.

Females were more likely to desert the nest than males, and those that did often produced more offspring within a season than parents that retained their mate.

Plovers that divorced also dispersed across greater distances between breeding attempts to look for new mates.

Their findings suggested that a range of factors including the adult sex ratio, the length of breeding season and adult lifespan affect the fidelity and parenting behavior of these birds, rather than simply being due to the species. Their study also showed that successful nesting leads to divorce, whereas nest failure leads to retention of the mate for follow-up breeding. Plovers that divorced their partners and simultaneously deserted their broods produced more offspring within a season than parents that retained their mate.

Their work provides a counterpoint to theoretical expectations that divorce is triggered by low reproductive success, and supports adaptive explanations of divorce as a strategy to improve individual reproductive success. In addition, they showed that temperature may modulate these costs and benefits, and contribute to dynamic variation in patterns of divorce across plover breeding systems.

References: Halimubieke, N., Kupán, K., Valdebenito, J.O. et al. Successful breeding predicts divorce in plovers. Sci Rep 10, 15576 (2020). https://doi.org/10.1038/s41598-020-72521-6 link: https://www.nature.com/articles/s41598-020-72521-6