Table 1

An evolutionary view - vegetative desiccation tolerance in plants

Order/

Tolerance characteristics

Developmental complexity

Mechanisms of tolerance

Liverworts/

Rapid desiccation tolerated;

Anatomically primitive

Cell integrity maintained during drying

hornworts/

Some protection mechanisms

No vasculature

Rehydration leads to damage

mosses

focus on repair mechanisms

Rapid recovery

photosynthetic-apparatus maintained

Presence of non-reducing sugars, dehydrins and

rehydrins appear

Pre-stress existence of mRNA in RNPs

Selaginellales,

Slower desiccation required;

Vascular tissues develop

Isoetales,

photosynthetic-apparatus maintained

Scarcity of data

Lycopodiales

Epidermis appears

Equisetum/

Slow desiccation required

Increasing anatomical and

Scarcity of data

Ferns

developmental complexity

Epidermis appears

Gymnosperms

No vegetative desiccation

Beginning seed desiccation

Scarcity of data

tolerance

tolerance

Angiosperms

(Re)-discovery of vegetative

Established seed desiccation

Transcripts for proteins typical for drying

desiccation tolerance

tolerance

seeds induced in vegetative tissues

Monocots

Slow desiccation required

Transcripts of unknown function homologous

Poaceae

Focus on protection of

to constitutively expressed moss genes

Liliaceae

existing structures

are induced

Dicots

Photosynthetic-apparatus either maintained

LEA proteins, sugars and oligosaccharides,

Hamamelidaceae

or reduced during desiccation

Dehydrins and rehydrins in complex gene families

Labiatae

Tolerance inducible, ABA influence, sugars may be

Gesneriaceae

present or inducible

Scrophulariaceae

Transcription factors, vesicular traffic

Included are major systematic orders of plants in increasing organizational complexity and following plant appearance during evolution. Monocots - plants with a single cotyledon (for example, grasses [Poaceae]; Sporobolus stapfianus is a desiccation tolerant species in the Poaceae family); dicots - two cotyledons (for example, Arabidopsis thaliana; Craterostigma plantagineum is in this class). Tortula ruralis is, among the mosses, the best studied desiccation tolerant species. ABA, abscisic acid; LEA, late embryogenesis abundant.

Bohnert Genome Biology 2000 1:reviews1010.1   doi:10.1186/gb-2000-1-2-reviews1010