Cardamine :Leaf Architecture

Theertha · April 9, 2024, 2:57pm

How do we know which is simple and compund leaf?

Why compund leaf is splitted into many leaflets? Is there any specific reason for it?

Do we know the pattern of leaf in cardamine based on its emergence? As per my (@shalinisharma98 )understanding, the compund leaves that are emerging first, they are having less number of leaflets while the leaves that are emerging later they possess more leaflets compared to early emerged leaves, What could be reason behind it?

The above Summary was by @shalinisharma98 .Do you agree @Abhi0703 ?

Are we clear about the leaf types in cardamine!? @shalinisharma98 @Abhi0703 @Enas & others.

Following are the cardamine photos from CUBE homelabs.

Cardamine complexity of leaf morphology Ref. Chatshaala discussion @⁨shalini CUBE⁩ @⁨Theertha⁩ @⁨Smiti⁩ for maintaining continuity. From CUBE Archives. Photo mcarunan.

Cardamine first true leaf 27/1/24.I had sown the fresh Cardamine seeds sent to me by @⁨Theertha⁩ on 6thDec’23.So the seeds germinated after 52days of dormancy.Homelab Kolkata BatulP

Photo of a cardamine plant from CUBE LAB, HBCSE, Mumbai featuring the emerging bud. Can you guess which leaf stage the plant is at? What is the leaf shape of cardamine called? Date: Unknown (Probably of 2017). Source: Archive.

Update on cardamine plant

Date:- 01-02-2024
Time:- 04:00 pm
Photo taken by :- Shalini Sharma (CUBE DSC).

Spotted Cardamine in AND College in one of the pot.
Date : 12th February 2024.
Enas Shirin Fatma.

@⁨Smiti⁩ had an interesting worries about her cardamine.
Can you please share your worries regarding cardamine plant that you are having . @⁨Smiti⁩
How many different types of leaves cardamine had ? @⁨Aditya Joshi⁩ @⁨Lakshmy CUBE⁩
How simple leaves of cardamine different from compound leaves ?
⁩ @⁨~Dhanraj⁩ @⁨Aditya Joshi⁩
How the compound leaves of a cardamine different from each other ,does the number of leaf let increase bottom to top . @⁨Smiti⁩.

How many different types of leaves we can find in this picture @⁨Smiti⁩ @⁨Aditya Joshi⁩ &others .

References shared during chatshaala

Paper published from IISC Bangalore about the transition from simple to compound leaves: Will this help us understand the leaf transition of Cardamine from simple to compound?

In this study, the authors identified two gene families that regulate the development of simple leaves through the proteins they code for, in a plant called Arabidopsis thaliana – a popular model organism in plant biology. These gene families – CIN-TCP and KNOX-II – encode proteins called transcription factors that suppress the formation of new leaflets at the margin, thereby giving rise to simple leaves. The researchers simultaneously suppressed multiple members of the two gene families; this caused the simple leaves to become super-compound leaves that gave rise to leaflets indefinitely. However, when the authors independently suppressed either of the two gene families, the leaves did not turn into compound leaves, suggesting that the genes work in concert. Besides providing insights into plant development, in the long run, the findings could initiate and nurture innovations in the food industry. As Krishna Reddy Challa, a former PhD student at MCB and co-lead author of the study, says, “one could use this technique to alter the shape of the salad leaves as one chooses, or increase their biomass. For instance, you could change the shape of a spinach leaf to look like lettuce.” Indian Institute of Science

How would you explain your research outcomes to the non-scientific community?

Leaves primarily grow in the planar dimension and form the largest biological surface on earth. They can be divided into two types based on their shape; simple and compound. Simple leaves – as found in plants such as spinach, mango, oak, and Arabidopsis thaliana – have a single leaf blade with a smooth, serrated, or wavy margin. On the other hand, leaves of tomato, neem or Cardamine hirsuta form compound structure where leaf blade is dissected into multiple leaflets. Though scientists have converted compound leaves to simpler or more complex forms by genetic manipulation, no simple leaves have thus far been converted to compound form, suggesting that our understanding on the genetic regulation of leaf shape is still fragmented.

Our recent work published in Nature Plants reports the conversion of the simple Arabidopsis leaf into a super-compound form with never-ending leaflet formation.

Following are the Context to curriculum WhatsApp group:

[09/04, 11:04 am] Abhijeet CUBE: Are you saying cardamine had simple leaves earlier and then it changed to compound? @⁨Theertha⁩ ?

[09/04, 11:07 am] Arunan sir : @⁨Abhijeet CUBE⁩ Let’s post photo of a Cardamine plant.

Surely, we may see different kinds of leaves in the same plant in a certain pattern.
Please post a photo. @⁨Abhijeet CUBE⁩
Let’s all learn together.

[09/04, 11:09 am] Arunan sir : Photos are real catalysts for evidence based scientific discussions. @⁨Abhijeet CUBE⁩ @⁨Theertha⁩

Simple leaves are seen in the earlier stages of cardamine, later compound leaves arises,this is what i meant by transition from simple leaf to compound leaves.Photo: Theertha,CUBE Homelab, cherukkad, Kozhikode.

Photo showing Cardamine leaves with a
Simple leaf and a compound leaf.
CUBE Homelab, cherukkad, Kozhikode.
Theertha .

Simple leaves in cardamine.
CUBE Homelab, cherukkad, Kozhikode.
Theertha .

Compound leaves in cardamine.
CUBE Homelab, cherukkad, Kozhikode.
Theertha .

Theertha · August 30, 2024, 6:01am

1)Why is Cardamine considered a potential alternative to Arabidopsis thaliana?
2)What are the similarities between Cardamine and Arabidopsis thaliana?
3)Why might a plant model like Arabidopsis be unfamiliar to students who have completed their MSc?@⁨Suma CUBE⁩ @⁨Swaha CUBE⁩ @⁨~Smiti⁩ @⁨Seethalakhmi⁩ and others.

Research questions addressed today:

How does leaf development occur in plants?
Is there any expression of genes involved?
Homeobox gene in Plants and Animals
Cardamine has both simple and compound leaves. How might gene expression contribute to this?
How do mutations in fruit flies result in two pairs of wings?@⁨~Smiti⁩ @⁨Suma CUBE⁩ @⁨Swaha CUBE⁩ and others

Reference shared in Chatshaala:29/08/2024

In plants with simple leaves, knox genes are expressed exclusively in the meristem and stem, but in dissected leaves, they are also expressed in leaf primordia, suggesting that they may play a role in the diversity of leaf form. This hypothesis is supported by the intriguing phenotypes found in gain-of-function mutations where knox gene misexpression affects leaf and petal shape. The role of knox genes in plant development - PubMed

[29/08, 9:49 pm] Theertha: Arabidopsis thaliana is a model plant that is primarily found in the western Himalayas of India. It has also been found in Himachal Pradesh, Jammu & Kashmir, Sikkim, Uttar Pradesh, and Uttarakhand. Some specimens of A. thaliana are preserved in Indian herbaria.

[29/08, 9:49 pm] Theertha: Arabidopsis, Indian connectionhttps://www.jstor.org/stable/26495059
[29/08, 9:49 pm] Theertha: In multicellular organisms, the coordination of cell proliferation and expansion is fundamental for proper organogenesis, yet the molecular mechanisms involved in this coordination are largely unexplored. In plant leaves, the existence of this coordination is suggested by compensation, in which a decrease in cell number triggers an increase in mature cell size. To elucidate the mechanisms of compensation, we isolated five new Arabidopsis (Arabidopsis thaliana) mutants (fugu1–fugu5) that exhibit compensation. Analysis of Leaf Development in fugu Mutants of Arabidopsis Reveals Three Compensation Modes That Modulate Cell Expansion in Determinate Organs - PMC
[29/08, 9:50 pm] Theertha: Leaves show a wide range of shapes that results from the combinatory variations of two main parameters: the relative duration of the morphogenetic phase and the pattern of dissection of the leaf margin. To further understand the mechanisms controlling leaf shape, we have studied the interactions between several loci leading to increased dissection of the Arabidopsis leaf margins. Thus, we have used (i) mutants in which miR164 regulation of the CUC2 gene is impaired, (ii) plants overexpressing miR319/miRJAW that down-regulates multiple TCP genes and (iii) plants overexpressing the STIMPY/WOX9 gene. Through the analysis of their effects on leaf shape and KNOX I gene expression, we show that these loci act in different pathways. We show, in particular, that they have synergetic effects and that plants combining two or three of these loci show dramatic modifications of their leaf shapes. Finally, we present a working model for the role of these loci during leaf development. Plants | Free Full-Text | Combinations of Mutations Sufficient to Alter Arabidopsis Leaf Dissection
[29/08, 9:50 pm] Theertha: knox genes encode homeodomain-containing transcription factors that are required for meristem maintenance and proper patterning of organ initiation. In plants with simple leaves, knox genes are expressed exclusively in the meristem and stem, but in dissected leaves, they are also expressed in leaf primordia, suggesting that they may play a role in the diversity of leaf form. The role of knox genes in plant development - PubMed
[29/08, 9:50 pm] Theertha: Knotted1-like homeobox (KNOX) proteins are homeodomain transcription factors that maintain an important pluripotent cell population called the shoot apical meristem, which generates the entire above-ground body of vascular plants. KNOX proteins regulate target genes that control hormone homeostasis in the meristem and interact with another subclass of homeodomain proteins called the BELL family. Studies in novel genetic systems, both at the base of the land plant phylogeny and in flowering plants, have uncovered novel roles for KNOX proteins in sculpting plant form and its diversity. Here, we discuss how KNOX proteins influence plant growth and development in a versatile context-dependent manner. KNOX genes: versatile regulators of plant development and diversity - PubMed

Group photograph of participants:29/08/2024

Follow up WhatsApp group discussion:

[30/08, 7:08 am] Arunan sir : Arabidopsis in India? @⁨Theertha⁩ Why no BREAKING NEWS story? @⁨Suma CUBE⁩ @⁨Kiran CUBE⁩ @⁨Aditya Joshi⁩ @⁨~Snigahh!⁩
[30/08, 7:10 am] Arunan sir : Please give a summary on Arabidopsis and it’s Indian connection. @⁨Theertha⁩
Why no excitement? @⁨Suma CUBE⁩ @⁨Kiran CUBE⁩
Let’s all learn together.
[30/08, 7:14 am] Arunan sir : What about this KNOX I gene and its role in compound leaf formation? @⁨Theertha⁩ @⁨Suma CUBE⁩ @⁨Kiran CUBE⁩ @⁨Amirtha CUBE⁩
[30/08, 7:17 am] Arunan sir: What is the role of shoot apical meristem? @⁨Theertha⁩ @⁨Suma CUBE⁩ @⁨Sunitha Mam⁩ @⁨Chithra Ma’am⁩ @⁨~Ajita Banerjee⁩
[30/08, 9:47 am] Smiti: Both my favourite powerful model systems in one picture!

I think as we addressed the Research questions as mention here like leave Development from simple to compound in cardamine plant and changes from egg to adult or complete metamorphosis in fruit fly and butterfly all these are related to developmental biology which later directed us to Developmental Genetics as in which genes are active at what Shage of life cycle
[30/08, 9:48 am] smiti: Like here on board @⁨Theertha⁩ gave example of Cardamine in which x gene is responsible for formation of compound leave and as It is not expressed at early stage of developement but later it is expressed and we observe compound leaves.

2nd example here is mutation taking place in Homeobox gene of fruit fly giving rise to Bithorax (2 thorax) and 4 wing fly and this mutation took place during pupa stage, is It? @⁨Theertha⁩ @⁨Suma CUBE⁩ @⁨Seethalakhmi⁩ @⁨Amirtha CUBE⁩ @⁨~GTP⁩ and others
[30/08, 9:50 am] smiti: Classical developmental genetics is concerned with the mechanisms by which mutation, recombination, and lateral gene transfer in DNA influence the information available to a zygote and its cellular progeny.

https://www.sciencedirect.com/topics/neuroscience/developmental-genetics#:~:text=Classical%20developmental%20genetics%20is%20concerned%20with%20the%20mechanisms%20by%20which%20mutation%2C%20recombination%2C%20and%20lateral%20gene%20transfer%20in%20DNA%20influence%20the%20information%20available%20to%20a%20zygote%20and%20its%20cellular%20progeny.
[30/08, 10:51 am] Theertha: The thorax of a fruit fly has three segments: the second segment, from which one pair of wings arises, and the third segment, where the halteres are located. When a mutation occurs in the third thoracic segment, it can cause a pair of wings to arise from this segment instead of the halteres.

A) Ubx is responsible for all of the differences between the second (T2) and third (T3) thoracic segments. Ubx loss-of-function mutations transform halteres (green box, center panel) into wings (left panel); Ubx gain-of-function in T2 transforms the wings into halteres (right panel). B) In this study, tissue-specific chromatin immunoprecipitation was performed with pure populations of haltere or T3 leg imaginal discs, both of which express Ubx in all cells (green) and express Hth (red) in the subset of cells that will give rise to proximal appendages and body wall.https://www.researchgate.net/figure/A-Ubx-is-responsible-for-all-of-the-differences-between-the_fig1_51042428

[30/08, 10:53 am] Theertha: According to this reference, in plants, a simple leaf does not express the KNOX gene, whereas a compound leaf shows expression of the KNOX gene. A gain-of-function mutation can cause a transition from a simple leaf to a compound leaf, while a loss-of-function mutation in the Ultrabithorax gene can result in a fruit fly having two wings instead of the usual arrangement. Both KNOX and Ultrabithorax are homeobox genes.What do you say @⁨~Smiti⁩ @⁨Suma CUBE⁩ and others.
[30/08, 10:57 am] Arunan sir : What exactly is the process, in this case of cells deciding to differentiate to form wings? @⁨Theertha⁩
Is it similar to simple leaf giving way to compound leaf, in Cardamine? @⁨Theertha⁩ @⁨~Smiti⁩ @⁨Suma CUBE⁩ and others

[30/08, 10:57 am] Arunan sir : What exactly is the process, in this case of cells deciding to differentiate to form wings? @⁨Theertha⁩
Is it similar to simple leaf giving way to compound leaf, in Cardamine? @⁨Theertha⁩ @⁨~Smiti⁩ @⁨Suma CUBE⁩ and others
[30/08, 4:44 pm] Suma CUBE: when a gene is not being expressed in simple leaf what is the purpose of this mutation . what is exactly happening after this mutation The mutation is in KNOX gene right @⁨Theertha⁩
[30/08, 5:24 pm] Theertha: If we have a vegitable(salad vegetable),the leaf is the part which had high nutrition and better taste.But the leaf is simple ,if we could convert simple to a compound leaf with an increase the laminal(leaf ) size , could it be a good idea to induce Knox mutation and check if the leaf is safe for human consumption? @⁨Suma CUBE⁩
[30/08, 5:25 pm] Theertha: If a plant that only having a simple leaf that can be form compound leaf by inducing a mutation in the Knox 1 gene and wise versa(by reversing the sequence through another induced mutation).
(As per the reference it says gain of function mutation in Knox gene)

In our context, Cardamine which had both simple and compound leaf suggesting the Knox 1 expression is present in compound leaf and the expression is absent in simple leaf.

I propose ,In the early vegetative stage the simple leaf will form , at that time Knox gene is not expressed.But when the time for compound leaf to emerge,by getting some signals from the shoot Apical meristem to leaf primordia (where leaf form)the Knox gene is getting expressed and compound leaf will form.
[30/08, 5:34 pm] Arunan sir : What could trigger Knox gene or any gene to express? @⁨Theertha⁩
What could be the process for a gene to express? @⁨Theertha⁩ @⁨Suma CUBE⁩ @⁨~Smiti⁩ @⁨Amirtha CUBE⁩
[30/08, 5:36 pm] Arunan sir: Are we going by some reference? @⁨Theertha⁩ @⁨Suma CUBE⁩
[30/08, 5:49 pm] Theertha: The class I KNOTTED1-like homeobox *(KNOXI) genes are involved in the maintenance of the meristem activity of SAM, while the initiation of leaves requires downregulation of KNOXI genes at the incipient site1,2,3.In simple-leafed species such as Arabidopsis thaliana, downregulation of KNOXI genes in leaf primordia is permanent, whereas in most compound-leafed eudicot species, including the tomato (Solanum lycopersicum) and Cardamine hirsuta, KNOXI genes are reactivated in leaf primordia after initiation of leaf development4,5,6.Genetic control of compound leaf development in the mungbean (Vigna radiata L.) | Horticulture Research