Chinese scientists find key genes to fight against crop parasites

Chinese Academy of Sciences Headquarters

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Knocking out SbSLT1/2 reduces the amount of SL in root exudates, decreases Striga germination, and potentially mitigates yield loss in infested regions. In this illustration, on the left is shown the wild-type (WT) sorghum releasing SLs, which trigger Striga germination and infection, resulting in yield loss. "Striga" means "witch" in Latin, and the ghost depicted represents its harm to crops. On the right, the SbSLT1/2-knockout sorghum demonstrates a strong ability to resist Striga.

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Credit: XIE Qi

Chinese scientists have identified two key genes responsible for sorghum's resistance to Striga, a parasitic plant that causes significant crop losses. The breakthrough, which also highlights the potential of AI to predict key amino acid sites in strigolactone (SL) transporters, could have wide-ranging applications in enhancing parasitic plant resistance across various crops.

This study, published in Cell, was conducted by Prof. XIE Qi's team at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, in collaboration with five other institutions.

Striga, also known as "witchweed," along with other parasitic plants like Orobanche, relies on host plants for nutrients and water, severely affecting crop yields and agricultural ecosystems. Striga alone infests over 50 million hectares of farmland in Africa, causing annual economic losses of $1.5 billion and affecting over 300 million people. In China, Striga is found in regions such as Guangdong and Yunnan, while Orobanche poses a threat to crops like sunflowers and tomatoes in Inner Mongolia and Xinjiang.

Sorghum is one of the plants susceptible to Striga infestation. Sorghum roots release SLs, a class of plant hormones that help recruit mycorrhizal fungi for nutrient uptake. Unfortunately, Striga seeds dormant in the soil detect these SL signals, which trigger Striga germination and subsequent infestation of the host plant.

In this study, the researchers analyzed transcriptome data from sorghum roots under phosphorus-deficient conditions and strigolactone (SL) treatmen separately. The scientists identified two ABCG family SL transporter genes: Sorghum bicolor SL transporter 1 (SbSLT1) and Sorghum bicolor SL transporter 2 (SbSLT2). They determined that the SbSLT1 and SbSLT2 proteins control the efflux of SLs and knocking out the associated genes inhibits SL secretion. Under these conditions, Striga is unable to germinate and infect the host.

AI-based predictions further identified a conserved phenylalanine residue critical for SL transport. This residue is found not only in sorghum, but also in SL transporters across other monocot crops like maize, rice, and millet, as well as dicotyl crops such as sunflowers and tomatoes, suggesting a conserved mechanism across species. Molecular biology and cellular biology experiments demonstrate the key function of this residue.

Field trials conducted in Striga-prone areas showed that sorghum with knocked-out SbSLT1 and SbSLT2 genes exhibited 67–94% lower infestation rates and 49–52% less yield loss. These findings offer valuable genetic resources and technical support for breeding Striga-resistant sorghum varieties.

The researchers emphasized that the discovery of SbSLT1 and SbSLT2 could provide crucial tools for combating parasitic plants, potentially addressing food security challenges in countries severely affected by parasitic plants, especially African and Asian countries, thereby contributing to regional peace and stability. Future research will focus on validating these genes in crops such as maize, tomato, and millet, with the goal of advancing the commercialization of Striga-resistant crops.

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Journal

Cell

DOI

10.1016/j.cell.2025.01.022 

Method of Research

Meta-analysis

Subject of Research

Cells

Article Title

Resistance to Striga Parasitism through Reduction of Strigolactone Exudation

Article Publication Date

12-Feb-2025

 

New study identifies brain region that can prevent aggressive social behavior and induce pro social behavior

The Mount Sinai Hospital / Mount Sinai School of Medicine

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Graphic representation of study findings. 

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Credit: Mount Sinai Health System

 

 

Nature article entitled:
A critical role for the cortical amygdala in shaping social encounters
[https://doi.org/10.1038/s41586-024-08540-4]

Bottom Line: Neural activity in the cortical amygdala determines whether mice engage in aggressive or pro-social behavior 

Results: By performing a network analysis on whole-brain activity of male mice, we identified the cortical amygdala – an olfactory cortical structure – as a key brain region in promoting aggression. This brain region is activated by olfactory cues from male mice and by aggressive behavior. Inhibiting the cortical amygdala reduces aggressive behavior and induces pro-social behavior.

Why the Research Is Interesting:  This is the first study that identified a brain region that can prevent aggressive social behavior and induce pro social behavior.

Study Conclusions: Cells in the cortical amygdala respond specifically to male social stimuli thereby enhancing their salience and promoting attack behaviour.

First Author: Antonio Aubry, PhD
Senior Author: Scott Russo, PhD

Said Mount Sinai's Dr. Aubry of the research: “Aggression is an evolutionarily conserved behavior that controls social hierarchies and protects valuable resources. However, aggression can become maladaptive and pose threats to patients and caregivers. Modeling and understanding the behavioral etiology of aggressive behavior is therefore a health priority. In order to discover novel brain regions which are involved in aggression behavior, we performed a network analysis on brain wide activity at the single cell level.  This analysis identified the cortical amygdala, an olfactory cortical structure, as a key brain region in promoting aggression. This brain region is activated by olfactory cues from male mice and by aggressive behavior. Importantly, we found that inhibiting the cortical amygdala and it’s downstream circuits reduces aggressive behavior and induces pro-social behavior."

Keywords: Social behavior, aggression, cortical amygdala

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Journal

Nature

DOI

10.1038/s41586-024-08540- 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

A crucial role for the cortical amygdala in shaping social encounters

Article Publication Date

12-Feb-2025

 

Symbiotic bacteria ride along with marine cells in ocean’s upper layer

Marine Biological Laboratory

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By Wynne Parry

Just as the human body serves as a habitat for bacteria and other microbes, diverse, tiny organisms known as protists host their own microbiomes.

In new research published this week, a team led by Marine Biological Laboratory (MBL) scientists reveals that symbiotic bacteria often accompany single-celled protists in the ocean’s upper layer. Some of these symbionts, they discovered, are close relatives of bacteria pathogenic to animals, including humans.

“We know there are many symbionts in the world, but it was surprising to find that smallest, and most common predatory protists in the ocean have symbionts living with them,” says senior author Alexandra Worden, a senior scientist at MBL.

The protists her team studied are among the smallest in the ocean, measuring two to five microns, roughly the size of a dust particle or small mold spore.

The discovery of these symbiont lineages sheds light on the evolution of their bacterial relatives – whether symbionts or pathogens – insight that could help researchers understand disease vectors and the infections they cause in people.

Marine Protists are Elusive – and Essential

Protists are a diverse, catchall group. Most are unicellular, but with features that disqualify them from grouping with other types of life like animals, plants, fungi, bacteria, and archaea.

In the ocean, some protists function like plants, using light to manufacture their own food. Others, such as choanoflagellates, which are animals’ closest living unicellular relatives, envelop and digest still smaller cells. Ocean ecosystems depend on these predators and browsers to consume plant-like phytoplankton and other bacteria, and, in turn, become food for the tiny marine animals that fish eat. 

Scientists have had difficulty studying their contribution to marine food webs, in part because they can’t coax these organisms to grow in the lab. To get around this problem, Worden developed a method for examining individual protist cells fresh out of the ocean using equipment brought onto research vessels – rather than in stable, climate-controlled rooms in hospitals and research centers, as usual.

“It has been an incredible team effort by students, technicians, and postdocs in the lab over the years to make these discoveries. A lot of perseverance and work within the constraints of the expeditions and weather!” she says.

After retrieving water samples from the North Pacific and other locations, researchers in her group stain the protists’ food vacuole — equivalent to their stomachs. This stain makes it possible to select the protists that interest the researchers: those eating other things. After separating out the individual protists, the researchers then identify the bacteria within or attached to them using genetic sequencing. (Their analysis looked only at whole bacteria, not the ones the protists had recently eaten.)

Then they worked with collaborators in the BIOS-SCOPE project, taking what they had learned to analyze data collected on a monthly basis over multiple years in the North Atlantic, in order to understand seasonal dynamics.

Studying these symbionts is essential to fully understanding the protists’ biology, similar to how the human microbiome is crucial to our health, according to Worden. “They could be fundamental to how the protists live and grow in the ocean,” she says.

Harmful or Helpful? Symbiosis in Protists and in Humans

Unlike the human microbiome, which hosts trillions of symbiont cells, the much smaller protists can likely carry a small handful.

In research published in Nature Microbiology in 2022, Worden’s team used on-board cell sorting to identify one type of bacterial symbiont, dubbed Comchoano, within a species of choanoflagellate. It and four other groups of bacteria showed up within the many protist cells analyzed for the present study. Of the four new symbiont lineages, three have close evolutionary links to human pathogens that live as symbionts in insects, such as ticks.

One of these lineages is closely related to Coxiella, a group that contains the germs responsible for the flu-like Q fever. Meanwhile, the others belong within a group that includes Rickettsia, members of which can cause Rocky Mountain spotted fever, typhus, and other infections.

In spite of their links to disease in mammals, it's not clear if these microbes help or harm their protist hosts. Context makes all the difference in these relationships, says Worden, noting that bacteria such as Rickettsia aid their insect hosts, only causing disease once they arrive within humans or other mammals.

“There’s an arc from our symbionts, all the way to disease in humans,” says first author Fabian Wittmers, who conducted the research while a BIOS-SCOPE graduate student in Worden’s Lab. 

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The Marine Biological Laboratory (MBL) is dedicated to scientific discovery – exploring fundamental biology, understanding marine biodiversity and the environment, and informing the human condition through research and education. Founded in Woods Hole, Massachusetts in 1888, the MBL is a private, nonprofit institution and an affiliate of the University of Chicago.

 

  

Strategy for discovering protist – bacterial interactions in the ocean. The strategy relied on working at-sea where uncultivated cells could be interrogated without any form of fixation. The cartoon shows the approach, moving from the upper left corner clockwise. The active phagocytic vacuoles of uncultivated predatory protists were illuminated with fluorescent dye(s) and the unique emission from these stains was used to discriminate the predatory protists from other microbes and photosynthetic protists (phytoplankton). This involved use of light scatter signatures and autofluorescence optimized to select and exclude photosynthetic protists and other microbes. After sorting into individual wells with a variety of controls (see Method Details) plates were frozen until subsequent steps depicted in the cartoon. From Wittmers et al., Cell Host & Microbe, 2025.

Credit

From Wittmers et al., Cell Host & Microbe, 2025 (Alex Worden Lab, MBL).

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Journal

Cell Host & Microbe

DOI

10.1016/j.chom.2025.01.009 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Symbionts of Predatory Protists are Widespread in the Oceans and Related to Animal Pathogens

Article Publication Date

12-Feb-2025

 

China Jurassic fossil discovery sheds light on bird origin

Chinese Academy of Sciences Headquarters

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3D Reconstruction of Baminornis zhenghensis.

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Credit: Video by Ren Wenyu

A research team led by Professor WANG Min from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences has discovered two bird fossils in Jurassic-era rocks from Fujian Province in southeast China. These rocks date back approximately 149 million years. The fossils fill a spatiotemporal gap in the early evolutionary history of birds and provide the evidence yet that birds were diversified by the end of the Jurassic period. 

This study was published in Nature.

Birds are the most diverse group of terrestrial vertebrates. Certain macroevolutionary studies suggest that their earliest diversification dates back to the Jurassic period (approximately 145 million years ago). However, the earliest evolutionary history of birds has long been obscured by a highly fragmentary fossil record, with Archaeopteryx being the only widely accepted Jurassic bird. 

Although Archaeopteryx had feathered wings, it closely resembled non-avialan dinosaurs, notably due to its distinctive long, reptilian tail—a stark contrast to the short-tailed morphology of modern and Cretaceous birds. Recent studies have questioned the avialan status of Archaeopteryx, classifying it as a deinonychosaurian dinosaur, the sister group to birds. This raises the question of whether any unambiguous records of Jurassic birds exist.

In this study, the researchers named one of the two fossils Baminornis zhenghensis. This fossil displays a unique combination of features, including derived ornithothoracine bird-like shoulder and pelvic girdles, as well as a plesiomorphic hand structure resembling that of non-avialan dinosaurs. These characteristics highlight the role of mosaic evolution in early bird development. Notably, Baminornis zhenghensis has a short tail ending in a compound bone called the pygostyle, a feature also observed in living birds.

"Previously, the oldest record of short-tailed birds is from the Early Cretaceous. Baminornis zhenghensis is the sole Jurassic and the oldest short-tailed bird yet discovered, pushing back the appearance of this derived bird feature by nearly 20 million years," said Prof. WANG, the lead and corresponding author of the study. 

The researchers used several methods to explore the position of Baminornis zhenghensis in the evolutionary tree of birds. The results showed that Baminornis zhenghensis was only just derived than Archaeopteryx and it represents one of the oldest birds.

“If we take a step back, and reconsider the phylogenetic uncertainty of Archaeopteryx, we do not doubt that Baminornis zhenghensis is the true Jurassic bird,” said Dr. ZHOU Zhonghe from IVPP, co-author of the study.

The second fossil is incomplete, consisting solely of a furcula. The researchers performed geometric morphometric and phylogenetic analyses to explore its relationship with other non-avialan and avialan theropods. Interestingly, the results supported the referral of this furcula to Ornithuromorpha, a diverse group of Cretaceous birds. Given its poor preservation, however, the team refrained from naming a new taxon based on this single bone, and its placement within birds needs further fossil evidence.

Figure 1. Photograph and interpretive line drawing of the 150-million-yaer-old bird Baminornis zhenghensis

The evolutionary tree showing the position of Baminornis zhenghensis, and the morphometric space illustrating the modular evolution of different body parts 

Figure 2. The evolutionary tree showing the position of Baminornis zhenghensis, and the morphometric space illustrating the modular evolution of different body parts

Figure 3. A possible Jurassic ornithuromorph furcula from the 150-million-yaer-old Zhenghe Fauna

Credit

Image by WANG Min

Figure 4. Life reconstruction of the Jurassic bird Baminornis zhenghensis from the Zhenghe Fauna

Credit

Image by ZHAO Chuang

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Journal

Nature

DOI

10.1038/s41586-024-08410-z 

Article Title

Earliest short-tailed bird from the Late Jurassic of China

Article Publication Date

12-Feb-2025