Abstract
BACKGROUND: A structural phenomenon seen in certain lineages of angiosperms that has captivated many scholars including Charles Darwin is the evolution of plant carnivory. Evidently, these structural features collectively termed carnivorous syndrome, evolved to aid nutritional acquisition from attracted, captured and digested prey. We now understand why plant carnivory evolved but how carnivorous plants acquired these attributes remains a mystery. In an attempt to understand the evolution of Nepenthes pitcher and to shed more light on its role in prey digestion, we analyzed the transcriptome data of the highly specialized Nepenthes khasiana leaf comprising the leaf base lamina, tendril and the different parts/zones of the pitcher tube viz. digestive zone, waxy zone and lid. RESULTS: In total, we generated around 262 million high-quality Illumina reads. Reads were pooled, normalized and de novo assembled to generate a reference transcriptome of about 412,224 transcripts. We then estimated transcript abundance along the N. khasiana leaf by mapping individual reads from each part/zone to the reference transcriptome. Correlation-based hierarchical clustering analysis of 27,208 commonly expressed genes indicated functional relationship and similar cellular processes underlying the development of the leaf base and the pitcher, thereby implying that the Nepenthes pitcher is indeed a modified leaf. From a list of 2386 differentially expressed genes (DEGs), we identified transcripts encoding key enzymes involved in prey digestion and protection against pathogen attack, some of which are expressed at high levels in the digestive zone. Interestingly, many of these enzyme-encoding genes are also expressed in the unopened N. khasiana pitcher. Transcripts showing homology to both bacteria and fungi were also detected; and in the digestive zone, fungi are more predominant as compared to bacteria. Taking cues from histology and scanning electron microscopy (SEM) photomicrographs, we found altered expressions of key regulatory genes involved in leaf development. Of particular interest, the expression of class III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII) and ARGONAUTE (AGO) genes were upregulated in the tendril. CONCLUSIONS: Our findings suggest that N. khasiana pitchers employ a wide range of enzymes for prey digestion and plant defense, harbor microbes and probably evolved through altered expression of leaf polarity genes.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 7
Claim · model-written summary
A reference transcriptome of about 412,224 transcripts was assembled from around 262 million reads.
- Taxon
- Nepenthes khasiana
Nepenthes khasianat0 - Outcome
- reference transcriptomee0
- Value
- about 412,224 transcriptse0
- Qualifier
- around 262 million high-quality Illumina readse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In total, we generated around 262 million high-quality Illumina reads. Reads were pooled, normalized and de novo assembled to generate a reference transcriptome of about 412,224 transcripts.”
t0“Nepenthes khasiana”
Claim · model-written summary
Clustering of 27,208 genes indicated shared processes in the leaf base and pitcher, supporting pitcher identity as a modified leaf.
- Taxon
- Nepenthes khasianaNepenthes khasianat0
- Organ / stage
- leaf base and the pitchere0
- Outcome
- functional relationship and similar cellular processese0
- Value
- 27,208 commonly expressed genese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Correlation-based hierarchical clustering analysis of 27,208 commonly expressed genes indicated functional relationship and similar cellular processes underlying the development of the leaf base and the pitcher, thereby implying that the Nepenthes pitcher is indeed a modified leaf.”
t0“Nepenthes khasiana”
Claim · model-written summary
Among 2386 differentially expressed genes, transcripts encode prey digestion and defense enzymes, some highly expressed in the digestive zone.
- Taxon
- Nepenthes khasianaNepenthes khasianat0
- Organ / stage
- digestive zonee0
- Outcome
- transcripts encoding key enzymes involved in prey digestion and protection against pathogen attacke0
- Value
- 2386 differentially expressed genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“From a list of 2386 differentially expressed genes (DEGs), we identified transcripts encoding key enzymes involved in prey digestion and protection against pathogen attack, some of which are expressed at high levels in the digestive zone.”
t0“Nepenthes khasiana”
Claim · model-written summary
Many digestive enzyme genes are expressed in unopened pitchers.
- Taxon
- N. khasianaNepenthes khasianae0
- Organ / stage
- unopened N. khasiana pitchere0
- Outcome
- enzyme-encoding genes are also expressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“many of these enzyme-encoding genes are also expressed in the unopened N. khasiana pitcher.”
t0“Nepenthes khasiana”
Claim · model-written summary
Bacterial and fungal homologous transcripts were detected, with fungi more predominant in the digestive zone.
- Taxon
- Nepenthes khasianaNepenthes khasianat0
- Organ / stage
- digestive zonee0
- Outcome
- fungi are more predominante0
- Direction
- more predominante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transcripts showing homology to both bacteria and fungi were also detected; and in the digestive zone, fungi are more predominant as compared to bacteria.”
t0“Nepenthes khasiana”
Claim · model-written summary
Key regulatory genes involved in leaf development showed altered expression.
- Taxon
- Nepenthes khasianaNepenthes khasianat0
- Organ / stage
- leafe0
- Outcome
- altered expressions of key regulatory genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we found altered expressions of key regulatory genes involved in leaf development.”
t0“Nepenthes khasiana”
Claim · model-written summary
HD-ZIPIII and AGO genes were upregulated in tendrils.
- Taxon
- Nepenthes khasianaNepenthes khasianat0
- Organ / stage
- tendrile0
- Gene
- class III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII) and ARGONAUTE (AGO) genese0
- Outcome
- expressione0
- Direction
- upregulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the expression of class III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII) and ARGONAUTE (AGO) genes were upregulated in the tendril.”
t0“Nepenthes khasiana”