Immunity and resistance differ in plants. Immunity involves specific antibodies or white blood cells fighting infection, but plants lack an adaptive immune system. Plant resistance is heritable and helps plants avoid or minimize damage from pathogens. There are two types of immunity in plants - PAMP-triggered immunity (PTI) activates defenses when pathogens are recognized. Effector-triggered immunity (ETI) occurs when plants recognize pathogen effectors. Resistance types include non-preference which makes plants unattractive, antibiosis which harms or kills pathogens, and tolerance which allows plants to remain healthy despite damage.
2. SUBMITTED BY:
AHMAD KAMAL 2020-AG-3358
NUMAN SADIQ 2020-AG-3360
UMAIR ALI 2020-AG-3356
AMJAD ALI 2020-AG-3355
Submitted To:
Prof. Dr. Ghulam Mustafa Sahi
3. Immunity Resistance
The ability of an organism to resist a
Particular infection or toxin by the action
of specific antibodies or sensitized
white blood cells.
Unlike vertebrates, plants do not have an
adaptive immune system. Nonetheless,
plants can launch specific, self-tolerant
immune responses and establish immune
memory
Plant resistance is normally defined as the
heritable ability of plants to escape
attacking enemies, partially or fully,
thus minimizing the amount of damage
experienced by the plant
4. •TYPES OF IMMUNITY:
I. Pathogen-associate molecular patterns (PAMPs)-triggered immunity(PTI)
II. Effector-triggered immunity (ETI)
5. Pathogen-associate molecular patterns
(pamps)-triggered immunity(PTI)
• Pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) are recognized by host cell
surface-localized pattern-recognition receptors (PRRs) to activate plant immunity. PAMP-
triggered immunity (PTI) constitutes the first layer of plant immunity that restricts pathogen
proliferation. PTI signaling components often are targeted by various Pseudomonas
syringae virulence effector proteins, resulting in diminished plant defenses and increased bacterial
virulence. Some of the proteins targeted by pathogen effectors have evolved to sense the effector
activity by associating with cytoplasmic immune receptors classically known as resistance
proteins. This allows plants to activate a second layer of immunity termed effector-triggered
immunity (ETI). Recent studies on PTI regulation and P. syringae effector targets have uncovered
new components in PTI signaling. Although MAP kinase (MAPK) cascades have been considered
crucial for PTI, emerging evidence indicates that a MAPK-independent pathway also plays an
important role in PTI signaling.
6. Effector-triggered immunity (ETI)
• Effector triggered immunity (ETI) is the plant immune response that specifically include transcription
processes in the host nucleus. For example, successful pathogens endorse pathogenesis by injecting
effector proteins into the plant cell. These Avr proteins which are avirulent in nature contributes to
pathogen virulence in three ways: by acting as transcription factors, by disturbing histone packing and
chromatin configuration, by directly targeting activity of transcription factor and eventually releasing
nutrients for the survival of pathogen.Plant ETI therefore respond to pathogen infection by activation
of transcription factors including a range of pathogenesis related genes in and around the invaded
plant cell for the synthesis of chemical substances such as salicylic acid (SA), ethylene (ET),
jasmonic acid (JA), various antimicrobial compounds as well as lignification and strengthening of
cell-wall. Thus accumulated salicylic acid in the infected areas binds to the receptor NPR3 of the PR
genes for the degradation of the infected cell by a process analogous to the apoptosis- a programmed
cell death found in animals
7. Types of resistance.
I. NON-PREFERENCE (anti-xenosis)
II. ANTIBIOSIS
III. TOLERANCE.
8. Non-preference (anti-xenosis)
Host plants that express non-preference affect the way an insect pest perceives
the desirability of the host plant. Non-preference plants either provide stimuli
that are unattractive to the pest (color, odor, texture such as downy hairs) or fail
to provide stimuli that are attractive to the pest. In this way, non-preference
plants affect the behavior of pests.
9. ANTIBIOSIS
Antibiosis is a type of resistance in which the host plant causes injury, death,
reduced longevity, or reduced reproduction of the pest. Often both a resistant
and susceptible variety will have the same basic response to a pest, but the
resistant variety will respond more quickly or more dramatically than the
susceptible variety, reducing the amount of damage the pest causes. Plants that
express antibiosis affect the biology of pests.
10. Tolerance
Host plants that express tolerance are resistant to pest damage because they can
remain healthy and yield well despite the damage. These plants must also be
able to heal wounds and fight diseases that enter through wounds. The
effectiveness of host plant resistance can vary by location because insect pests
of the same species can vary somewhat by location. For instance, a Colorado
potato beetle in Colorado is slightly different than a Colorado potato beetle in
Wisconsin.
