From plant science to gardening

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Spring in my garden

Last week this blog celebrated its third birthday. In that time I have gone from being a research scientist to working as an editor for a scientific journal and so the involvement of plants in my life has changed somewhat. Working with plants was one of my favourite parts of my old role in research and so its perhaps not surprising that I now do quite a bit of gardening in my spare time.

Until about a year ago, the extent of my gardening experience was a few herbs in pots outside and a bunch of low-maintenance houseplants. I wasn’t always very good at looking after these plants, so branching out to a whole, albeit small, garden has all been a bit of an experiment!

I’m happy to say that my gardening experiment has overall been pretty successful so far. I’ve managed to grow some edible vegetables and my garden looks much tidier and more colourful than it did when I moved in. Most importantly, now that I have an office job, I’ve really enjoyed having a good excuse to spend lots of my leisure time outside. However, my first year in the garden hasn’t been completely plain sailing as I ran into a few problems and disasters along the way. Here are the most useful lessons I have learnt along the way:

Be on the alert for pests – they WILL find your favourite plants. Last year, slugs and snails attacked my salad leaves and destroyed the marigolds I was growing. I tried out a few different methods to deter them from eating the rest of my crops and eventually settled on copper tape. Slugs and snails don’t like crawling over copper and so I could use the tape to make a pretty good barrier to defend a lot of my vegetable crops. Unfortunately, the same cannot be said for my nasturtiums (Tropaeolum majus), which became infested with hundreds of blackflies (a type of aphid) and withered and died soon after.

That plant support or structure might look tidy, but will it withstand the weather? I must admit that the first few structures I built to support plants were not all as robust as they should have been because I didn’t really appreciate how windy it would be in my garden. The canes holding up my tomatoes were blown over on several occasions, and the netting structure protecting my cabbages nearly flew away in a winter gale.

When digging in an overgrown patch of ground, keep an eye out for plants you might want to keep. Last year, I got a good crop of potatoes from the handful of tubers left in the vegetable patch by the previous occupants of the house. And just this week I discovered some parsnips growing amongst the grass of the overgrown allotment I’ve recently taken on with some friends. Being fairly hopeless at plant identification, I didn’t know what potato or parsnip plants looked like until I stumbled into them.

Work out what types of plants you like to grow and then grow them. I like to feel “productive” when I’m gardening, so I can spend hours tending to my vegetable patch and then forget to water my houseplants. As a result, I’ve tried to fill as much of my garden with fruit and vegetables as possible, and then used low-maintenance decorative plants to fill in the gaps and really shaded areas.

My main gardening project for this year is to work on an allotment with my friends. The plot hasn’t been cultivated in a few years so was pretty overgrown, but since we took on the tenancy a couple of months ago, we have managed to clear some parts of it and plant some soft fruit crops. Watch this space.

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The new project…

Tracing the roots of an ancient friendship

 

Figure 1

An AM fungus (yellow) contacts the surface of a plant root. The nuclei of the plant cells are visible as blue spots. Image adapted from ref 3. Credit: Andrea Genre and Mara Novero (CC BY 3.0).

Plants need nutrients to be able to grow. Unfortunately, many of these nutrients can be scarce in the soil and therefore hard to get hold of. To get around this problem, most plants are able to form friendly relationships – known as symbioses – with soil microbes that can provide them with certain nutrients in exchange for sugars.

Today, around 80% of land plants form symbioses with a group of fungi known as arbuscular mycorrhizal (AM) fungi (1). Fossil evidence suggests that this symbiosis first emerged around 450 million years ago. This is around the same time that plants first started to colonise land. The transition from water to the dry and harsh environments on land would have presented many challenges to the early land plants, for example, how to avoid losing too much water. Another challenge would have been how to access essential nutrients that their ancestor (a type of green algae) would have gained directly from the water.

The liverworts, hornworts and mosses are thought to be the earliest groups of land plants (2). Since the AM symbiosis is widespread in these groups, it has been suggested that this symbiosis is one of the innovations that helped these primitive plants to survive on land.

Previous studies have identified many plant genes that are needed for AM symbiosis in legumes and other land plants. These genes can be split into two main groups: some are in a signalling pathway needed for the plant and fungus to communicate with each other, and others are activated later to allow the fungus to infect into the roots of the plant. Recently, Pierre-Marc Delaux and colleagues used a technique called phylogenetics to analyse genetic material from many different algae, liverworts, hornworts and mosses with the aim of finding out when the AM symbiosis genes first appeared (2).

Delaux et al. show that these plant genes emerged in stages, starting from before earliest plants colonised land. The signalling pathway genes appeared first, and are present in the algae that are thought to be the closest relatives of land plants, the Charophytes (2). On the other hand, the infection genes appear to be missing from the algae, but are present in the liverworts, hornworts and mosses.

These findings suggest that the algal ancestors of land plants were pre-adapted to interact with fungi. Currently, there is no evidence to suggest that the Charophytes are able to form AM symbioses themselves. Therefore, it is possible the signalling pathway evolved to allow algae to interact with other microbes and was later altered to allow the early land plants to interact with AM fungi.

Reference:

  1. Parniske, M. (2008). Arbuscular mycorrhiza: the mother of plant root endosymbioses. Nat Rev Microbiol, 6, 763-75.
(Good review of AM symbiosis, but unfortunately this article is hidden behind a paywall…)
  2. Delaux P, Radhakrishnan GV, Jayaraman D, Cheema J, Malbreil M, Volkening JD, Sekimoto H, Nishiyama T, Melkonian M, Pokorny L, Rothfels CJ, Sederoff HW, Stevenson DW, Surek B, Zhang Y, Sussman MR, Dunand C, Morris RJ, Roux C, Wong GK-S, Oldroyd GED, Ané JM. 2015. Algal ancestor of land plants was preadapted for symbiosis. Proceedings of the National Academy of Sciences of the United States of America. 2015, DOI: 10.1073/pnas.1515426112, PMID: 26438870
  3. Corradi N, Bonfante P. 2012. The Arbuscular Mycorrhizal Symbiosis: Origin and Evolution of a Beneficial Plant Infection. PLoS Pathog 8(4): e1002600. doi:10.1371/journal.ppat.1002600

The catch-22 of being a carnivorous plant

Guest post by Sonja Dunbar (@PlantSciSonja)

Plants, like any other organism, want to reproduce. The usual way that plants achieve this is known as sexual reproduction, where an egg cell and sperm from two different individuals fuse and then develop into a new plant. However, since plants are generally anchored to one spot, they can’t meet up to reproduce. Instead, they rely on a variety of more indirect methods to transport sperm to other plants. For example, many flowering plants (also known as angiosperms) recruit insect messengers to carry their sperm, safely packaged in pollen grains, from one plant to another. They use colourful, sometimes scented, flowers to attract potential pollinators and often reward them with a sugary drink, nectar, while coating them in the pollen the plant wants them to carry. But what if you are a plant that also eats insects?

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Some of the most well-known pollinators; bees and butterflies. Image credit: S. Dunbar

Carnivorous plants obtain nutrients from trapped insects to help them cope with a lack of important nutrients in their environment, such as nitrogen, that they need to grow (1). There are several different trap types, from snap traps, to flypaper traps and pitfall traps. The fact that carnivorous species are found in multiple different plant families suggests this strategy has arisen several times. Continue reading

On the origin of chloroplasts

Guest post by Joram Schimmeyer

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Chloroplasts in plant cells are easily identified under a microscope by their green colour. Image: J. Schimmeyer.

Of all the biological processes found on Earth, photosynthesis could be considered one of the most important. During photosynthesis, the energy from sunlight is used to build up sugars in the cells of plants, algae and some bacteria. These sugars can then be metabolised by the cells or other organisms that feed on them. Also, photosynthesis produces oxygen gas as a by-product, which is needed by most forms of life on earth. Without photosynthesis, life as we know it would not be possible.

In plants and algae, photosynthesis is carried out in tiny compartments inside cells called chloroplasts. This compartment contains a green pigment called chlorophyll, which is used to harvest light energy and is responsible for plants appearing green in colour. Chloroplasts vary greatly in shape and size, but they are all enclosed by two membranes and filled with even more membranes known as the thylakoid membrane system. The key players of photosynthesis are located within these thylakoid membranes; large groups of proteins use the light energy from chlorophyll to convert carbon dioxide form the atmosphere into sugars. The sugars can then be broken down to provide energy to drive growth and other cellular processes. Continue reading

Sudden oak death – a disease as ominous as its name

Guest post by Monica Lewandowski (@MMLewandowski52)

Sudden oak death is a disease that has killed millions of oaks (Quercus spp.) and tanoaks (Notholithocarpus densiflorus) in the western United States. First detected in California in the mid 1990s, it continues to steadily spread through northern California and Oregon forests, with the potential to wreak more havoc in forests and landscapes across the world.

The underlying cause of sudden oak death is a fungal-like organism, Phytophthora ramorum. The spores of P. ramorum are spread by wind, rain and human movement of infected plants. And more bad news – P. ramorum can infect much more than oaks. A strain of P. ramorum that infects larch trees is making headlines in the United Kingdom, where it’s better known as larch tree disease. Several species of trees and shrubs, herbaceous plants and even maidenhair fern are on P. ramorums “host” list (view regulated plant list in the United States). This is a cause for concern as losing one or more key plant species in a forest can lead to dramatic changes for both the flora and fauna of an ecosystem. Continue reading

Where’s the plant science in beef?

Guest post by Erin Sparks (@ErinSparksPhD)

Four years ago I became a first generation beef farmer. I had just started a postdoc studying the development of plant roots when my husband told me that his parents intended to give us beef cows as a wedding present. Whoa. Wait. What?!?!?! First of all, we live in a very small apartment – where are we going to put cows? Second of all, we know nothing about farming. Fear not fair reader, the good news is that my in-laws keep the cows for us and they are “many”-generation beef farmers so they know what they’re doing. Through their tutelage, I’m slowly becoming a beef farmer. I’ve learned about herd management, breeding, economics and more. Although all aspects of farming fascinate me, I wanted to tell you specifically about how plant science contributes to our farm.

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One of Erin’s cows and her new twins. Much like humans, twins are a rarity for bovine. Image credit: E. Sparks

We run a cow-calf operation, which means that we keep a herd of cows (100+ in total) and three bulls on the farm. These animals are bred and their calves are then sold to market. What do these animals eat? Feeding cattle is a basic cost-benefit analysis. If you pay more to feed your animals than the profit you gain, you can’t make a living. Although it is not as simple as that, because beef prices are constantly fluctuating, so you also have to consider market projections. On our farm, we strive to be self-sufficient for feeding our animals. This means we grow over 200 acres of hay that is rolled and stored. In the summer, the animals are grazing in the fields, but come winter, when the fields freeze over, the animals get fed these hay bales. Alternatively, you can raise animals on grain feed, but this is exceedingly more expensive. We save grain feed for the calves after weaning, and to increase growth before selling. Continue reading

On leaves and ligules

Guest post by Siva Chudalayandi (@sianj)

I love plants and a walk through the woods never fails to refresh my mind. I have been fortunate to have spent the last several years researching aspects of plant genetics and development. The cells of the plant leaves house many compartments called chloroplasts, which are the factories that make organic matter using just sunlight, water and carbon dioxide in a process called photosynthesis. Through this blog I’d like to pay tribute to this unique organ of plants.

Leaves occur in myriad shapes and forms. Sometimes they are large (e.g. banana leaves) or serrated (tomato leaves), or are needle-like, as seen on pine trees. However, like many other structural forms in biology they are made up of distinct substructures that are found in many different groups of plants. I live in the USA in the state of Iowa, an area that is flush with corn fields. Corn (maize) is a fascinating model to study how the leaves of the grasses and other monocot plants develop. The flat and wide portion of the leaf is called the leaf blade, while the part of the leaf that hugs the stem is called the sheath. The blade and sheath are separated by an outgrowth called the ligule and a loosely defined region called the auricle (Figure 1). This sheath and blade pattern is repeated in every leaf. Continue reading