Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the National Academy of Sciences  

The ability of parasitic plants to withdraw nutrients from their hosts depends on the formation of an infective structure known as the haustorium. How parasites regulate their haustoria numbers is poorly understood, and here, we uncovered that existing haustoria in the facultative parasitic plants Phtheirospermum japonicum and Parentucellia viscosa suppressed the formation of new haustoria located on distant roots. Using Phtheirospermum, we found that this effect depended on the formation of mature haustoria and could be induced through the application of external nutrients. To understand the molecular basis of this root plasticity, we analyzed hormone response and found that existing infections upregulated cytokinin-responsive genes first at the haustoria and then more distantly in Phtheirospermum shoots. We observed that infections increased endogenous cytokinin levels in Phtheirospermum roots and shoots, and this increase appeared relevant since local treatments with exogenous cytokinins blocked the formation of both locally and distantly formed haustoria. In addition, local overexpression of a cytokinin-degrading enzyme in Phtheirospermum prevented this systemic interhaustoria repression and increased haustoria numbers locally. We propose that a long-distance signal produced by haustoria negatively regulates future haustoria, and in Phtheirospermum , such a signaling system is mediated by a local increase in cytokinin to regulate haustoria numbers and balance nutrient acquisition.

DOI： 10.1073/pnas.2424557122

Open Access

Scopus

PubMed

Publisher：International Journal of Agronomy  

Striga hermonthica remains a major biological constraint to food production in sub-Saharan Africa. This study investigates the critical paradox underlying its persistent threat in western Kenya: Despite decades of research and the availability of numerous control measures, Striga infestation continues to expand. A field survey was conducted across twelve administrative units over three years (2019, 2022, and 2023), involving 174 farming households to assess their knowledge, practices, and the multifaceted factors contributing to the problem. Our findings reveal that while a majority of farmers are aware of and practice Striga control, infestation remains severe (69% of fields) and results in estimated maize yield losses of 47%. We identified key drivers perpetuating this gap between intervention and on-the-ground reality, including the continuous cultivation of susceptible staple crops driven by subsistence needs and evidence of Striga’s ecological expansion into new niches, such as higher altitudes. We conclude that the failure to control Striga is not merely a technical issue, but a systemic problem rooted in a combination of ecological and socioeconomic barriers. Our study highlights the need for a holistic approach that moves beyond agronomic techniques to inform the development of more effective and sustainable management strategies that address these underlying constraints.

DOI： 10.1155/ioa/1128845

Open Access

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.molcel.2024.09.004

Scopus

PubMed

Publisher：Cold Spring Harbor Laboratory  

Polar transport of the phytohormone auxin plays a crucial role in plant growth and response to environmental stimuli. Small-molecule tools that visualize auxin distribution in intact plants enable us to understand how plants dynamically regulate auxin transport to modulate growth. In this study, we developed a new fluorescent auxin probe, BODIPY-IAA2, which effectively visualizes auxin distribution in various plant tissues. We designed this probe to be transported by auxin transporters while lacking the ability to elicit auxin signaling. Using BODIPY as the fluorophore provides bright and stable fluorescence signals, making it suitable for live-imaging under standard fluorescent microscopy. We tested the probe with auxin reporter lines inArabidopsisand performed yeast two-hybrid assays. The results showed that BODIPY-IAA2 did not activate auxin signaling through the auxin receptor TIR1. However, BODIPY-IAA2 did mildly compete with both exogenous and endogenous auxins for transport, indicating that the probe is transported by auxin transportersin vivo. The probe not only enables visualization of its tissue distribution but also allows sub-cellular staining, including the endoplasmic reticulum and tip regions in elongating cells in moss. We also observed unusual staining patterns in the main root of non-model parasitic plants where genetic transformation is not feasible. Our new fluorescent auxin probe demonstrates significant potential for detailed studies on auxin transport and distribution across diverse plant species.

DOI： 10.1101/2024.09.11.612572

Language：English   Publisher：Plant and Cell Physiology  

Dormant seeds of the root parasitic plant Striga hermonthica sense strigolactones from host plants as environmental cues for germination. This process is mediated by a diversified member of the strigolactone receptors encoded by HYPOSENSITIVE TO LIGHT/KARRIKIN INSENSITIVE2 genes. It is known that warm and moist treatment during seed conditioning gradually makes dormant Striga seeds competent to respond to strigolactones, although the mechanism behind it is poorly understood. In this report, we show that plant hormone gibberellins increase strigolactone competence by up-regulating mRNA expression of the major strigolactone receptors during the conditioning period. This idea was supported by a poor germination phenotype in which gibberellin biosynthesis was depleted by paclobutrazol during conditioning. Moreover, live imaging with a fluorogenic strigolactone mimic, yoshimulactone green W, revealed that paclobutrazol treatment during conditioning caused aberrant dynamics of strigolactone perception after germination. These observations revealed an indirect role of gibberellins in seed germination in Striga, which contrasts with their roles as dominant germination-stimulating hormones in non-parasitic plants. We propose a model of how the role of gibberellins became indirect during the evolution of parasitism in plants. Our work also highlights the potential role for gibberellins in field applications, for instance, in elevating the sensitivity of seeds toward strigolactones in the current suicidal germination approach to alleviate the agricultural threats caused by this parasite in Africa.

DOI： 10.1093/pcp/pcad056

Web of Science

Scopus

PubMed

Language：English

Seed germination of a parasitic plant Striga hermonthica is elicited by strigolactones which are exuded from roots of host plants. Here, we describe a high-throughput germination assay and a method for visualizing in vivo strigolactone receptor functions with a fluorogenic probe.

DOI： 10.1007/978-1-0716-3965-8_5

Scopus

PubMed

J-GLOBAL

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： 10.5685/plmorphol.29.33

J-GLOBAL

Language：Japanese   Publisher：化学同人  

CiNii Research

J-GLOBAL