NIPGR scientists find a calcium channel that spreads a plant's alarm against insect attack
In one line: NIPGR researchers showed that the calcium channel CNGC13 carries a plant's alarm from an insect-damaged leaf to its other leaves, switching on their defences.
Published 1 November 2026. Written by Pratidin from the reports linked at the end; every fact checked by a separate review before publishing. How we work
Scientists at the National Institute of Plant Genome Research (NIPGR), New Delhi, have identified a calcium channel that helps a plant pass an alarm from a leaf being eaten by insects to its undamaged leaves. The protein, CYCLIC NUCLEOTIDE GATED CHANNEL13 (CNGC13), lets calcium ions flow into cells. The study, from the laboratory of Jyothilakshmi Vadassery with Misha Kumari as lead researcher, was published in the Proceedings of the National Academy of Sciences (PNAS) in 2026 under the title "The Ca2+ channel CYCLIC NUCLEOTIDE GATED CHANNEL13 regulates vasculature-mediated systemic Ca2+ and jasmonate signaling on herbivory". The team worked with Arabidopsis thaliana, a small mustard-family weed used as a model plant, and the tobacco cutworm Spodoptera litura, a caterpillar pest that feeds on many crops.
CNGC13 was strongly switched on by wounding and insect feeding and is found in the plant's vascular tissue, its system of veins. In mutant plants lacking it, the calcium signal reaching distant leaves was weaker and delayed, the defence hormone jasmonic acid built up less in those leaves, and defence compounds called glucosinolates were not mobilised properly. Caterpillars feeding on these mutants gained more weight, showing the plants were less protected. Plants that lacked both CNGC13 and CNGC19, a calcium channel earlier linked to defence against Spodoptera, were the most vulnerable. Glutamate receptor-like channels (GLRs) were already known to relay such long-distance alarms; the authors' preprint describes CNGC13 as working in a parallel branch, which suggests plants use more than one channel type to carry the signal.
Plants cannot run from attackers, so they rely on fast internal signals: calcium waves, electrical and hydraulic signals and reactive oxygen species travel from the wound and prime distant tissues to raise chemical defences. Knowing which proteins carry these signals gives breeders and genetic engineers targets for crops with stronger natural pest resistance, and the researchers suggest this could support more sustainable approaches to pest management. The work is basic research on a model plant; whether the same channel works the same way in crops such as mustard, cotton or soybean, and whether boosting it carries costs for growth, are open questions for further study.
Prelims facts
- NIPGR, New Delhi, identified CNGC13, a calcium channel that relays the alarm from an insect-damaged leaf to undamaged leaves; the work appeared in PNAS in 2026.
- CNGC13 is induced by wounding and insect feeding and is located in the plant's vascular tissue.
- Without CNGC13, Arabidopsis plants showed weaker systemic calcium and jasmonic acid signals, and Spodoptera litura larvae feeding on them gained more weight.
- The finding adds a second route alongside glutamate receptor-like channels (GLRs) for long-distance defence signalling in plants.
- Such signalling proteins are potential targets for breeding or engineering crops with stronger natural pest resistance.
Quick recall
- Which institute identified CNGC13's role in plant alarm signalling?
- National Institute of Plant Genome Research (NIPGR), New Delhi.
- In which journal was the CNGC13 study published?
- Proceedings of the National Academy of Sciences (PNAS), 2026.
- What kind of protein is CNGC13?
- A cyclic nucleotide gated channel that lets calcium ions into cells.
- Where in the plant is CNGC13 located?
- In the vascular tissue (the veins).
- Which insect was used in the CNGC13 study?
- Spodoptera litura, the tobacco cutworm.
- Which defence hormone built up less in distant leaves of cngc13 mutants?
- Jasmonic acid.
- Which channel family was already known to relay long-distance wound signals?
- Glutamate receptor-like channels (GLRs).
- Which plant family does Arabidopsis thaliana belong to?
- The mustard family (Brassicaceae).
Prelims practice question
CNGC13, recently identified by Indian scientists in the context of plant defence, is best described as:
- a bacterial toxin gene used in insect-resistant crops
- a calcium channel that helps relay alarm signals to undamaged leaves
- a pheromone used in insect traps
- an enzyme that synthesises chlorophyll
Show answer
Answer: (b) a calcium channel that helps relay alarm signals to undamaged leaves. CNGC13 (cyclic nucleotide gated channel 13) is a calcium-permeable channel in the plant's vascular tissue. NIPGR scientists showed it carries systemic calcium and jasmonate signals after insect attack. Bacterial toxin genes such as cry genes from Bacillus thuringiensis are a different technology.
Use this in UPSC Mains: previous-year questions
Recurring theme: Biotechnology for agriculture: basic plant science, pest resistance and farmers' welfare
How can biotechnology help to improve the living standards of farmers?
How to use thisUse the CNGC13 finding as an Indian example of basic research that could lead to pest-resistant crops and lower input costs for farmers.
- NIPGR, New Delhi (PNAS, 2026) found the calcium channel CNGC13 relays a plant's alarm against insects to undamaged leaves.
- Plants lacking CNGC13 had weaker jasmonic acid defences and Spodoptera litura caterpillars gained more weight on them.
- Such signalling genes are targets for breeding or engineering crops that need fewer pesticide sprays.
This question is on biotechnology and clean energy; the plant defence research fits only its general biotechnology dimension.
Mains practice question
Understanding how plants signal and respond to insect attack can open new routes to sustainable pest management. Discuss with reference to recent Indian research. (150 words)
Model answer
In 2026 scientists at NIPGR, New Delhi, reported in PNAS that the calcium channel CNGC13 relays a plant's alarm from an insect-damaged leaf to undamaged leaves.
What the research shows
- CNGC13 is induced by wounding and Spodoptera litura feeding and sits in vascular tissue.
- Mutants lacking it had weaker systemic calcium and jasmonic acid signals; caterpillars gained more weight on them.
- It works alongside glutamate receptor-like channels, so plants use multiple alarm routes.
Routes to sustainable pest management
- Breeding or gene editing to strengthen natural defence signalling.
- Priming defences instead of blanket pesticide spraying, fitting integrated pest management.
- Less pesticide use reduces residues, resistance in pests and harm to pollinators.
Caveats
- Findings are in a model plant; crop validation is needed.
- Stronger defences may reduce growth or yield.
- Regulatory clarity for gene-edited crops matters.
Basic plant science like this is the foundation for the next generation of pest-resistant crops.
The basics
Why this matters
Plants lose a large part of their yield to insects, and farmers respond with pesticides that leave residues, kill pollinators and breed resistance. A different approach is to understand and strengthen the plant's own defences. The NIPGR finding on CNGC13 is a small but real step in that direction, and it touches several examinable ideas: cell signalling, plant hormones, model organisms and integrated pest management.
How a plant raises the alarm
A chewing insect damages cells. Damaged cells release signals, and within seconds to minutes calcium levels rise inside cells near the wound. The signal then travels, mostly through the veins, to distant leaves, which start making defence hormones and chemicals before the insect reaches them.
- 1DamageA Spodoptera litura caterpillar chews a leaf; damaged cells release danger signals
- 2Local calcium riseCalcium channels open and calcium floods into cells near the wound
- 3Long-distance relayCNGC13 in the vascular tissue, alongside GLR channels, carries the calcium signal to undamaged leaves
- 4Hormone build-upJasmonic acid accumulates in distant leaves
- 5Chemical defenceGlucosinolate-based defences are mobilised, making leaves less palatable
Why calcium?
Cells keep calcium inside their main fluid at very low levels and pump it out constantly. That makes a sudden rise easy to detect, so calcium works as a switch. Proteins such as calmodulin read the rise and turn on genes. See Calcium signalling in plant cells.
What the experiment showed
The team compared normal Arabidopsis with mutants lacking CNGC13. See Arabidopsis thaliana as a model plant for why this weed is used. The hormone involved is explained in Jasmonic acid and plant defence.
- Strong, fast calcium signal in distant leaves
- Jasmonic acid builds up in distant leaves
- Caterpillars gain less weight
- Weaker, delayed systemic calcium signal
- Less jasmonic acid in distant leaves
- Caterpillars gain more weight
From lab to field
The practical goal is crops that defend themselves better, used within Integrated pest management so that chemical sprays become a last resort. That will need testing in crops and careful checks for any cost to yield.
Go deeper
Why it matters for UPSC
GS3 asks about biotechnology for farmers, Indian achievements in science, and sustainable agriculture. Prelims often tests plant hormones, model organisms and pest management concepts.
The core idea
Plants cannot move away from attackers, so they rely on internal signals. Calcium signalling in plant cells is the first step: when a leaf is chewed, calcium floods into cells. CNGC13, in the veins, relays this signal to distant leaves, where Jasmonic acid and plant defence switch on chemical defences. The team proved this in Arabidopsis thaliana as a model plant. In the long run such knowledge could support Integrated pest management with crops that defend themselves better.
Numbers and dates to remember
- 2026: study published in PNAS by NIPGR, New Delhi.
- Insect: Spodoptera litura (tobacco cutworm).
- Plant: Arabidopsis thaliana (mustard family).
- Two channel families relay wound signals: CNGCs and GLRs.
- Earlier-known defence channel: CNGC19.
Where to go next
- Calcium signalling in plant cells: why calcium is a cellular switch.
- Jasmonic acid and plant defence: the hormone of the insect alarm.
- Arabidopsis thaliana as a model plant: why a weed teaches us about crops.
- Integrated pest management: where this science could be applied.
Go deeper: can a plant's own alarm replace pesticides?
What is new. Earlier work had shown that glutamate receptor-like channels carry wound-induced calcium and electrical signals to distant leaves. The NIPGR study adds CNGC13 as a parallel route in the vascular tissue, and shows that without it, Jasmonic acid and plant defence responses in distant leaves are weaker and caterpillars grow better. Plants lacking both CNGC13 and CNGC19 were the most vulnerable, so several channels share the work.
Why this is promising. Pesticide overuse leaves residues, kills natural enemies and pollinators, and breeds resistant pests. Strengthening Calcium signalling in plant cells or the hormone response could make crops harder to eat from the start. This fits Integrated pest management, which treats chemicals as a last resort.
Why caution is needed. The work is in Arabidopsis thaliana as a model plant, not a crop. Defence is costly: plants that are always on alert can grow more slowly. Turning the finding into a variety would need gene editing or breeding, field trials and regulatory approval. Pests can also evolve to suppress plant signals.
India's angle. NIPGR is an autonomous institute of the Department of Biotechnology. Basic research of this kind builds the knowledge base for indigenous crop biotechnology, a theme UPSC links to farmers' incomes and food security.
Calcium signalling in plant cells
Why calcium acts as a cell's alarm switch
In one line: Cells use sudden rises in calcium ions in their cytosol as a signal that something has changed, from touch and cold to insect attack.
How it works
Pumps keep calcium in the cytosol very low compared with outside the cell or inside stores. When a stimulus opens calcium channels, calcium rushes in and its level spikes. Sensor proteins such as calmodulin and calcium-dependent protein kinases read the spike and switch on responses, including defence genes.
The channels
Plants have several channel families. Arabidopsis has 20 cyclic nucleotide gated channels (CNGCs) and 20 glutamate receptor-like channels (GLRs). The NIPGR study shows CNGC13 helps carry the calcium signal over long distances after wounding.
Where to go next
Jasmonic acid and plant defence
The hormone that turns an alarm into armour
In one line: Jasmonic acid is a plant hormone made from fatty acids that coordinates defence against chewing insects and wounding.
What it does
After wounding, plants make jasmonic acid and convert it into its active form, jasmonoyl-isoleucine. This switches on genes for defence proteins and chemicals, such as protease inhibitors that upset insect digestion and toxic compounds. Another hormone, salicylic acid, mainly handles defence against many disease-causing microbes.
Glucosinolates
In the mustard family, defence includes glucosinolates, sulphur-containing compounds that the enzyme myrosinase turns into toxic isothiocyanates when tissue is crushed. In the NIPGR study, jasmonic acid in distant leaves and glucosinolate-based defences depended on CNGC13.
Where to go next
Arabidopsis thaliana as a model plant
Why a small weed is the lab rat of plant science
In one line: Arabidopsis thaliana, thale cress, is a small mustard-family weed that plant biologists use the way medical researchers use mice.
Why it is used
It has a small genome, which in 2000 became the first plant genome to be sequenced. It completes its life cycle in about six weeks, produces many seeds, and is easy to grow in labs. Large collections of mutants exist, so researchers can switch off one gene, such as CNGC13, and see what changes.
Limits
It is not a crop. Findings must be tested in crops such as mustard, rice or cotton before they can help farmers.
Where to go next
Integrated pest management
Where plant defence science meets farmers' fields
In one line: Integrated pest management (IPM) combines several methods to keep pests below damaging levels, using chemical pesticides only when needed.
The methods
IPM uses resistant varieties, crop rotation and timely sowing, biological control with natural enemies and biopesticides, mechanical tools such as pheromone and light traps, regular field monitoring against economic threshold levels, and need-based, judicious use of chemicals. In India, pesticides are regulated under the Insecticides Act, 1968.
Why it is relevant here
Crops with stronger built-in defence signalling, of the kind the CNGC13 research points to, would be a resistant-variety tool within IPM, reducing sprays against polyphagous pests such as Spodoptera litura.
Where to go next
Take the 1 November 2026 quiz: 30 Prelims-style questions with answers